Method and device for determining feedback resource in NR V2X

ABSTRACT

A method for performing wireless communication by a first device and a device for supporting same are provided. The method may comprise the steps of: receiving a physical sidelink shared channel (PSSCH) from a second device; determining a physical sidelink feedback channel (PSFCH) resource associated with the PSSCH; and transmitting hybrid automatic repeat request (HARQ) feedback to the second device on the PSFCH resource. Here, the PSFCH resource can be determined on the basis of a sub channel associated with the PSSCH, a slot associated with the PSSCH, a cast type of communication between the first device and the second device, an ID of the first device, and a source ID of the second device.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.17/572,035, filed on Jan. 10, 2022, which is a continuation pursuant to35 U.S.C. § 119(e) of International Application PCT/KR2020/008063, withan international filing date of Jun. 22, 2020, which claims the benefitof Korean Patent Application No. 10-2019-0083374, filed on Jul. 10,2019, Korean Patent Application No. 10-2019-0083454, filed on Jul. 10,2019, U.S. Provisional Patent Application No. 62/895,947, filed on Sep.4, 2019 and U.S. Provisional Patent Application No. 62/937,168, filed onNov. 18, 2019, the contents of which are hereby incorporated byreference herein in their entirety.

BACKGROUND OF THE DISCLOSURE Field of the Disclosure

This disclosure relates to a wireless communication system.

Related Art

Sidelink (SL) communication is a communication scheme in which a directlink is established between User Equipments (UEs) and the UEs exchangevoice and data directly with each other without intervention of anevolved Node B (eNB). SL communication is under consideration as asolution to the overhead of an eNB caused by rapidly increasing datatraffic.

Vehicle-to-everything (V2X) refers to a communication technology throughwhich a vehicle exchanges information with another vehicle, apedestrian, an object having an infrastructure (or infra) establishedtherein, and so on. The V2X may be divided into 4 types, such asvehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I),vehicle-to-network (V2N), and vehicle-to-pedestrian (V2P). The V2Xcommunication may be provided via a PC5 interface and/or Uu interface.

Meanwhile, as a wider range of communication devices require largercommunication capacities, the need for mobile broadband communicationthat is more enhanced than the existing Radio Access Technology (RAT) isrising. Accordingly, discussions are made on services and user equipment(UE) that are sensitive to reliability and latency. And, a nextgeneration radio access technology that is based on the enhanced mobilebroadband communication, massive Machine Type Communication (MTC),Ultra-Reliable and Low Latency Communication (URLLC), and so on, may bereferred to as a new radio access technology (RAT) or new radio (NR).Herein, the NR may also support vehicle-to-everything (V2X)communication.

FIG. 1 is a drawing for describing V2X communication based on NR,compared to V2X communication based on RAT used before NR. Theembodiment of FIG. 1 may be combined with various embodiments of thepresent disclosure.

Regarding V2X communication, a scheme of providing a safety service,based on a V2X message such as Basic Safety Message (BSM), CooperativeAwareness Message (CAM), and Decentralized Environmental NotificationMessage (DENM) is focused in the discussion on the RAT used before theNR. The V2X message may include position information, dynamicinformation, attribute information, or the like. For example, a UE maytransmit a periodic message type CAM and/or an event triggered messagetype DENM to another UE.

For example, the CAM may include dynamic state information of thevehicle such as direction and speed, static data of the vehicle such asa size, and basic vehicle information such as an exterior illuminationstate, route details, or the like. For example, the UE may broadcast theCAM, and latency of the CAM may be less than 100 ms. For example, the UEmay generate the DENM and transmit it to another UE in an unexpectedsituation such as a vehicle breakdown, accident, or the like. Forexample, all vehicles within a transmission range of the UE may receivethe CAM and/or the DENM. In this case, the DENM may have a higherpriority than the CAM.

Thereafter, regarding V2X communication, various V2X scenarios areproposed in NR. For example, the various V2X scenarios may includevehicle platooning, advanced driving, extended sensors, remote driving,or the like.

For example, based on the vehicle platooning, vehicles may move togetherby dynamically forming a group. For example, in order to perform platoonoperations based on the vehicle platooning, the vehicles belonging tothe group may receive periodic data from a leading vehicle. For example,the vehicles belonging to the group may decrease or increase an intervalbetween the vehicles by using the periodic data.

For example, based on the advanced driving, the vehicle may besemi-automated or fully automated. For example, each vehicle may adjusttrajectories or maneuvers, based on data obtained from a local sensor ofa proximity vehicle and/or a proximity logical entity. In addition, forexample, each vehicle may share driving intention with proximityvehicles.

For example, based on the extended sensors, raw data, processed data, orlive video data obtained through the local sensors may be exchangedbetween a vehicle, a logical entity, a UE of pedestrians, and/or a V2Xapplication server. Therefore, for example, the vehicle may recognize amore improved environment than an environment in which a self-sensor isused for detection.

For example, based on the remote driving, for a person who cannot driveor a remote vehicle in a dangerous environment, a remote driver or a V2Xapplication may operate or control the remote vehicle. For example, if aroute is predictable such as public transportation, cloud computingbased driving may be used for the operation or control of the remotevehicle. In addition, for example, an access for a cloud-based back-endservice platform may be considered for the remote driving.

Meanwhile, a scheme of specifying service requirements for various V2Xscenarios such as vehicle platooning, advanced driving, extendedsensors, remote driving, or the like is discussed in NR-based V2Xcommunication.

SUMMARY OF THE DISCLOSURE Technical Objects

Meanwhile, in NR V2X, a UE which has transmitted a PSSCH may receive aPSFCH related to the PSSCH. Therefore, the UE needs to efficientlydetermine a resource for the PSFCH.

Technical Solutions

In one embodiment, a method for performing, by a first device, wirelesscommunication is provided. The method may comprise: receiving, from asecond device, a physical sidelink shared channel (PSSCH); determining aphysical sidelink feedback channel (PSFCH) resource related to thePSSCH; and transmitting, to the second device, a hybrid automatic repeatrequest (HARQ) feedback based on the PSFCH resource. Herein, the PSFCHresource may be determined based on a sub-channel related to the PSSCH,a slot related to the PSSCH, a cast type of communication between thefirst device and the second device, an ID of the first device, and asource ID of the second device.

In one embodiment, a first device configured to perform wirelesscommunication is provided. The first device may comprise: one or morememories storing instructions; one or more transceivers; and one or moreprocessors connected to the one or more memories and the one or moretransceiver. The one or more processors may execute the instructions to:receive, from a second device, a physical sidelink shared channel(PSSCH); determine a physical sidelink feedback channel (PSFCH) resourcerelated to the PSSCH; and transmit, to the second device, a hybridautomatic repeat request (HARQ) feedback based on the PSFCH resource.Herein, the PSFCH resource may be determined based on a sub-channelrelated to the PSSCH, a slot related to the PSSCH, a cast type ofcommunication between the first device and the second device, an ID ofthe first device, and a source ID of the second device.

Effects of the Disclosure

The user equipment (UE) may efficiently perform SL communication.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a drawing for describing V2X communication based on NR,compared to V2X communication based on RAT used before NR.

FIG. 2 shows a structure of an NR system, based on an embodiment of thepresent disclosure.

FIG. 3 shows a functional division between an NG-RAN and a 5GC, based onan embodiment of the present disclosure.

FIG. 4 shows a radio protocol architecture, based on an embodiment ofthe present disclosure.

FIG. 5 shows a structure of an NR system, based on an embodiment of thepresent disclosure.

FIG. 6 shows a structure of a slot of an NR frame, based on anembodiment of the present disclosure.

FIG. 7 shows an example of a BWP, based on an embodiment of the presentdisclosure.

FIG. 8 shows a radio protocol architecture for a SL communication, basedon an embodiment of the present disclosure.

FIG. 9 shows a UE performing V2X or SL communication, based on anembodiment of the present disclosure.

FIG. 10 shows a procedure of performing V2X or SL communication by a UEbased on a transmission mode, based on an embodiment of the presentdisclosure.

FIG. 11 shows three cast types, based on an embodiment of the presentdisclosure.

FIG. 12 shows a diagram for explaining a problem in that a UE cannotdetect a specific PSFCH signal due to a large difference in receivepower at a PSFCH receiving end, based on an embodiment of the presentdisclosure.

FIG. 13 shows an example in which a plurality of PSFCHs are CDM, basedon an embodiment of the present disclosure.

FIG. 14 shows a procedure for a transmitting UE to select/determinePSFCH resource(s), based on an embodiment of the present disclosure.

FIG. 15 shows a method for determining a PSFCH resource set, based on anembodiment of the present disclosure.

FIG. 16 shows a method for securing one or more RB intervals between aunicast PSFCH and a common PSFCH, based on an embodiment of the presentdisclosure.

FIG. 17 shows a method in which different unicast PSFCH resources areselected/determined for each unicast session, based on an embodiment ofthe present disclosure.

FIG. 18 shows a procedure for a receiving UE to select/determine PSFCHresource(s), based on an embodiment of the present disclosure.

FIG. 19 shows a procedure for a transmitting UE to determine PSFCHresource(s), based on an embodiment of the present disclosure.

FIG. 20 shows a case in which N RB intervals exist between a pluralityof PSFCH resources, based on an embodiment of the present disclosure.

FIG. 21 shows a case in which N RB intervals exist between a pluralityof PSFCH resources, based on an embodiment of the present disclosure.

FIG. 22 shows a procedure for a receiving UE to determine PSFCHresource(s), based on an embodiment of the present disclosure.

FIG. 23 shows a method for a first device to determine a resource forreceiving HARQ feedback, based on an embodiment of the presentdisclosure.

FIG. 24 shows a method for a second device to determine a resource fortransmitting HARQ feedback, based on an embodiment of the presentdisclosure.

FIG. 25 shows a method for a first device to perform wirelesscommunication, based on an embodiment of the present disclosure.

FIG. 26 shows a method for a second device to perform wirelesscommunication, based on an embodiment of the present disclosure.

FIG. 27 shows a communication system 1, based on an embodiment of thepresent disclosure.

FIG. 28 shows wireless devices, based on an embodiment of the presentdisclosure.

FIG. 29 shows a signal process circuit for a transmission signal, basedon an embodiment of the present disclosure.

FIG. 30 shows another example of a wireless device, based on anembodiment of the present disclosure.

FIG. 31 shows a hand-held device, based on an embodiment of the presentdisclosure.

FIG. 32 shows a vehicle or an autonomous vehicle, based on an embodimentof the present disclosure.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

In the present disclosure, “A or B” may mean “only A”, “only B” or “bothA and B.” In other words, in the present disclosure, “A or B” may beinterpreted as “A and/or B”. For example, in the present disclosure, “A,B, or C” may mean “only A”, “only B”, “only C”, or “any combination ofA, B, C”.

A slash (/) or comma used in the present disclosure may mean “and/or”.For example, “A/B” may mean “A and/or B”. Accordingly, “A/B” may mean“only A”, “only B”, or “both A and B”. For example, “A, B, C” may mean“A, B, or C”.

In the present disclosure, “at least one of A and B” may mean “only A”,“only B”, or “both A and B”. In addition, in the present disclosure, theexpression “at least one of A or B” or “at least one of A and/or B” maybe interpreted as “at least one of A and B”.

In addition, in the present disclosure, “at least one of A, B, and C”may mean “only A”. “only B”, “only C”, or “any combination of A, B, andC”. In addition, “at least one of A, B, or C” or “at least one of A, B,and/or C” may mean “at least one of A, B, and C”.

In addition, a parenthesis used in the present disclosure may mean “forexample”. Specifically, when indicated as “control information (PDCCH)”,it may mean that “PDCCH” is proposed as an example of the “controlinformation”. In other words, the “control information” of the presentdisclosure is not limited to “PDCCH”, and “PDCCH” may be proposed as anexample of the “control information”. In addition, when indicated as“control information (i.e., PDCCH)”, it may also mean that “PDCCH” isproposed as an example of the “control information”.

A technical feature described individually in one figure in the presentdisclosure may be individually implemented, or may be simultaneouslyimplemented.

The technology described below may be used in various wirelesscommunication systems such as code division multiple access (CDMA),frequency division multiple access (FDMA), time division multiple access(TDMA), orthogonal frequency division multiple access (OFDMA), singlecarrier frequency division multiple access (SC-FDMA), and so on. TheCDMA may be implemented with a radio technology, such as universalterrestrial radio access (UTRA) or CDMA-2000. The TDMA may beimplemented with a radio technology, such as global system for mobilecommunications (GSM)/general packet ratio service (GPRS)/enhanced datarate for GSM evolution (EDGE). The OFDMA may be implemented with a radiotechnology, such as institute of electrical and electronics engineers(IEEE) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, evolved UTRA(E-UTRA), and so on. IEEE 802.16m is an evolved version of IEEE 802.16eand provides backward compatibility with a system based on the IEEE802.16e. The UTRA is part of a universal mobile telecommunication system(UMTS). 3rd generation partnership project (3GPP) long term evolution(LTE) is part of an evolved UMTS (E-UMTS) using the E-UTRA. The 3GPP LTEuses the OFDMA in a downlink and uses the SC-FDMA in an uplink.LTE-advanced (LTE-A) is an evolution of the LTE.

5G NR is a successive technology of LTE-A corresponding to a newClean-slate type mobile communication system having the characteristicsof high performance, low latency, high availability, and so on. 5G NRmay use resources of all spectrum available for usage including lowfrequency bands of less than 1 GHz, middle frequency bands ranging from1 GHz to 10 GHz, high frequency (millimeter waves) of 24 GHz or more,and so on.

For clarity in the description, the following description will mostlyfocus on LTE-A or 5G NR. However, technical features according to anembodiment of the present disclosure will not be limited only to this.

FIG. 2 shows a structure of an NR system, based on an embodiment of thepresent disclosure. The embodiment of FIG. 2 may be combined withvarious embodiments of the present disclosure.

Referring to FIG. 2 , a next generation-radio access network (NG-RAN)may include a BS 20 providing a UE 10 with a user plane and controlplane protocol termination. For example, the BS 20 may include a nextgeneration-Node B (gNB) and/or an evolved-NodeB (eNB). For example, theUE 10 may be fixed or mobile and may be referred to as other terms, suchas a mobile station (MS), a user terminal (UT), a subscriber station(SS), a mobile terminal (MT), wireless device, and so on. For example,the BS may be referred to as a fixed station which communicates with theUE 10 and may be referred to as other terms, such as a base transceiversystem (BTS), an access point (AP), and so on.

The embodiment of FIG. 2 exemplifies a case where only the gNB isincluded. The BSs 20 may be connected to one another via Xn interface.The BS 20 may be connected to one another via 5th generation (5G) corenetwork (5GC) and NG interface. More specifically, the BSs 20 may beconnected to an access and mobility management function (AMF) 30 viaNG-C interface, and may be connected to a user plane function (UPF) 30via NG-U interface.

FIG. 3 shows a functional division between an NG-RAN and a 5GC, based onan embodiment of the present disclosure. The embodiment of FIG. 3 may becombined with various embodiments of the present disclosure.

Referring to FIG. 3 , the gNB may provide functions, such as Inter CellRadio Resource Management (RRM), Radio Bearer (RB) control, ConnectionMobility Control, Radio Admission Control, Measurement Configuration &Provision, Dynamic Resource Allocation, and so on. An AMF may providefunctions, such as Non Access Stratum (NAS) security, idle statemobility processing, and so on. A UPF may provide functions, such asMobility Anchoring, Protocol Data Unit (PDU) processing, and so on. ASession Management Function (SMF) may provide functions, such as userequipment (UE) Internet Protocol (IP) address allocation, PDU sessioncontrol, and so on.

Layers of a radio interface protocol between the UE and the network canbe classified into a first layer (L1), a second layer (L2), and a thirdlayer (L3) based on the lower three layers of the open systeminterconnection (OSI) model that is well-known in the communicationsystem. Among them, a physical (PHY) layer belonging to the first layerprovides an information transfer service by using a physical channel,and a radio resource control (RRC) layer belonging to the third layerserves to control a radio resource between the UE and the network. Forthis, the RRC layer exchanges an RRC message between the UE and the BS.

FIG. 4 shows a radio protocol architecture, based on an embodiment ofthe present disclosure. The embodiment of FIG. 4 may be combined withvarious embodiments of the present disclosure. Specifically, FIG. 4(a)shows a radio protocol architecture for a user plane, and FIG. 4(b)shows a radio protocol architecture for a control plane. The user planecorresponds to a protocol stack for user data transmission, and thecontrol plane corresponds to a protocol stack for control signaltransmission.

Referring to FIG. 4 , a physical layer provides an upper layer with aninformation transfer service through a physical channel. The physicallayer is connected to a medium access control (MAC) layer which is anupper layer of the physical layer through a transport channel. Data istransferred between the MAC layer and the physical layer through thetransport channel. The transport channel is classified according to howand with what characteristics data is transmitted through a radiointerface.

Between different physical layers, i.e., a physical layer of atransmitter and a physical layer of a receiver, data are transferredthrough the physical channel. The physical channel is modulated using anorthogonal frequency division multiplexing (OFDM) scheme, and utilizestime and frequency as a radio resource.

The MAC layer provides services to a radio link control (RLC) layer,which is a higher layer of the MAC layer, via a logical channel. The MAClayer provides a function of mapping multiple logical channels tomultiple transport channels. The MAC layer also provides a function oflogical channel multiplexing by mapping multiple logical channels to asingle transport channel. The MAC layer provides data transfer servicesover logical channels.

The RLC layer performs concatenation, segmentation, and reassembly ofRadio Link Control Service Data Unit (RLC SDU). In order to ensurediverse quality of service (QoS) required by a radio bearer (RB), theRLC layer provides three types of operation modes, i.e., a transparentmode (TM), an unacknowledged mode (UM), and an acknowledged mode (AM).An AM RLC provides error correction through an automatic repeat request(ARQ).

A radio resource control (RRC) layer is defined only in the controlplane. The RRC layer serves to control the logical channel, thetransport channel, and the physical channel in association withconfiguration, reconfiguration and release of RBs. The RB is a logicalpath provided by the first layer (i.e., the physical layer or the PHYlayer) and the second layer (i.e., the MAC layer, the RLC layer, and thepacket data convergence protocol (PDCP) layer) for data delivery betweenthe UE and the network.

Functions of a packet data convergence protocol (PDCP) layer in the userplane include user data delivery, header compression, and ciphering.Functions of a PDCP layer in the control plane include control-planedata delivery and ciphering/integrity protection.

A service data adaptation protocol (SDAP) layer is defined only in auser plane. The SDAP layer performs mapping between a Quality of Service(QoS) flow and a data radio bearer (DRB) and QoS flow ID (QFI) markingin both DL and UL packets.

The configuration of the RB implies a process for specifying a radioprotocol layer and channel properties to provide a particular serviceand for determining respective detailed parameters and operations. TheRB can be classified into two types, i.e., a signaling RB (SRB) and adata RB (DRB). The SRB is used as a path for transmitting an RRC messagein the control plane. The DRB is used as a path for transmitting userdata in the user plane.

When an RRC connection is established between an RRC layer of the UE andan RRC layer of the E-UTRAN, the UE is in an RRC_CONNECTED state, and,otherwise, the UE may be in an RRC_IDLE state. In case of the NR, anRRC_INACTIVE state is additionally defined, and a UE being in theRRC_INACTIVE state may maintain its connection with a core networkwhereas its connection with the BS is released.

Data is transmitted from the network to the UE through a downlinktransport channel. Examples of the downlink transport channel include abroadcast channel (BCH) for transmitting system information and adownlink-shared channel (SCH) for transmitting user traffic or controlmessages. Traffic of downlink multicast or broadcast services or thecontrol messages can be transmitted on the downlink-SCH or an additionaldownlink multicast channel (MCH). Data is transmitted from the UE to thenetwork through an uplink transport channel. Examples of the uplinktransport channel include a random access channel (RACH) fortransmitting an initial control message and an uplink SCH fortransmitting user traffic or control messages.

Examples of logical channels belonging to a higher channel of thetransport channel and mapped onto the transport channels include abroadcast channel (BCCH), a paging control channel (PCCH), a commoncontrol channel (CCCH), a multicast control channel (MCCH), a multicasttraffic channel (MTCH), etc.

The physical channel includes several OFDM symbols in a time domain andseveral sub-carriers in a frequency domain. One sub-frame includes aplurality of OFDM symbols in the time domain. A resource block is a unitof resource allocation, and consists of a plurality of OFDM symbols anda plurality of sub-carriers. Further, each subframe may use specificsub-carriers of specific OFDM symbols (e.g., a first OFDM symbol) of acorresponding subframe for a physical downlink control channel (PDCCH),i.e., an L1/L2 control channel. A transmission time interval (TTI) is aunit time of subframe transmission.

FIG. 5 shows a structure of an NR system, based on an embodiment of thepresent disclosure. The embodiment of FIG. 5 may be combined withvarious embodiments of the present disclosure.

Referring to FIG. 5 , in the NR, a radio frame may be used forperforming uplink and downlink transmission. A radio frame has a lengthof 10 ms and may be defined to be configured of two half-frames (HFs). Ahalf-frame may include five 1 ms subframes (SFs). A subframe (SF) may bedivided into one or more slots, and the number of slots within asubframe may be determined based on subcarrier spacing (SCS). Each slotmay include 12 or 14 OFDM(A) symbols according to a cyclic prefix (CP).

In case of using a normal CP, each slot may include 14 symbols. In caseof using an extended CP, each slot may include 12 symbols. Herein, asymbol may include an OFDM symbol (or CP-OFDM symbol) and a SingleCarrier-FDMA (SC-FDMA) symbol (or Discrete Fourier Transform-spread-OFDM(DFT-s-OFDM) symbol).

Table 1 shown below represents an example of a number of symbols perslot (N^(slot) _(symb)), a number slots per frame (N^(frame,u) _(slot)),and a number of slots per subframe (N^(subfram,u) _(slot)) based on anSCS configuration (u), in a case where a normal CP is used.

TABLE 1 SCS (15*2^(u)) N^(slot) _(symb) N^(frame,u) _(slot)N^(subframe,u) _(slot)  15 KHz (u = 0) 14 10 1  30 KHz (u = 1) 14 20 2 60 KHz (u = 2) 14 40 4 120 KHz (u = 3) 14 80 8 240 KHz (u = 4) 14 16016

Table 2 shows an example of a number of symbols per slot, a number ofslots per frame, and a number of slots per subframe based on the SCS, ina case where an extended CP is used.

TABLE 2 SCS (15*2^(u)) N^(slot) _(symb) N^(frame,u) _(slot)N^(subframe,u) _(slot) 60 KHz (u = 2) 12 40 4

In an NR system, OFDM(A) numerologies (e.g., SCS, CP length, and so on)between multiple cells being integrate to one UE may be differentlyconfigured. Accordingly, a (absolute time) duration (or section) of atime resource (e.g., subframe, slot or TTI) (collectively referred to asa time unit (TU) for simplicity) being configured of the same number ofsymbols may be differently configured in the integrated cells.

In the NR, multiple numerologies or SCSs for supporting diverse 5Gservices may be supported. For example, in case an SCS is 15 kHz, a widearea of the conventional cellular bands may be supported, and, in casean SCS is 30 kHz/60 kHz a dense-urban, lower latency, wider carrierbandwidth may be supported. In case the SCS is 60 kHz or higher, abandwidth that is greater than 24.25 GHz may be used in order toovercome phase noise.

An NR frequency band may be defined as two different types of frequencyranges. The two different types of frequency ranges may be FR1 and FR2.The values of the frequency ranges may be changed (or varied), and, forexample, the two different types of frequency ranges may be as shownbelow in Table 3. Among the frequency ranges that are used in an NRsystem, FR1 may mean a “sub 6 GHz range”, and FR2 may mean an “above 6GHz range” and may also be referred to as a millimeter wave (mmW).

TABLE 3 Frequency Range Corresponding Subcarrier designation frequencyrange Spacing (SCS) FR1  450 MHz-6000 MHZ 15, 30, 60 kHz FR2 24250MHz-52600 MHz 60, 120, 240 kHz

As described above, the values of the frequency ranges in the NR systemmay be changed (or varied). For example, as shown below in Table 4, FR1may include a band within a range of 410 MHz to 7125 MHz. Morespecifically. FR1 may include a frequency band of 6 GHz (or 5850, 5900,5925 MHz, and so on) and higher. For example, a frequency band of 6 GHz(or 5850, 5900, 5925 MHz, and so on) and higher being included in FR1mat include an unlicensed band. The unlicensed band may be used fordiverse purposes, e.g., the unlicensed band for vehicle-specificcommunication (e.g., automated driving).

TABLE 4 Frequency Range Corresponding Subcarrier designation frequencyrange Spacing (SCS) FR1  410 MHz-7125 MHZ 15, 30, 60 kHz FR2 24250MHz-52600 MHz 60, 120, 240 kHz

FIG. 6 shows a structure of a slot of an NR frame, based on anembodiment of the present disclosure. The embodiment of FIG. 6 may becombined with various embodiments of the present disclosure.

Referring to FIG. 6 , a slot includes a plurality of symbols in a timedomain. For example, in case of a normal CP, one slot may include 14symbols. However, in case of an extended CP, one slot may include 12symbols. Alternatively, in case of a normal CP, one slot may include 7symbols. However, in case of an extended CP, one slot may include 6symbols.

A carrier includes a plurality of subcarriers in a frequency domain. AResource Block (RB) may be defined as a plurality of consecutivesubcarriers (e.g., 12 subcarriers) in the frequency domain. A BandwidthPart (BWP) may be defined as a plurality of consecutive (Physical)Resource Blocks ((P)RBs) in the frequency domain, and the BWP maycorrespond to one numerology (e.g., SCS, CP length, and so on). Acarrier may include a maximum of N number BWPs (e.g., 5 BWPs). Datacommunication may be performed via an activated BWP. Each element may bereferred to as a Resource Element (RE) within a resource grid and onecomplex symbol may be mapped to each element.

Meanwhile, a radio interface between a UE and another UE or a radiointerface between the UE and a network may consist of an L1 layer, an L2layer, and an L3 layer. In various embodiments of the presentdisclosure, the L1 layer may imply a physical layer. In addition, forexample, the L2 layer may imply at least one of a MAC layer, an RLClayer, a PDCP layer, and an SDAP layer. In addition, for example, the L3layer may imply an RRC layer.

Hereinafter, a bandwidth part (BWP) and a carrier will be described.

The BWP may be a set of consecutive physical resource blocks (PRBs) in agiven numerology. The PRB may be selected from consecutive sub-sets ofcommon resource blocks (CRBs) for the given numerology on a givencarrier.

When using bandwidth adaptation (BA), a reception bandwidth andtransmission bandwidth of a UE are not necessarily as large as abandwidth of a cell, and the reception bandwidth and transmissionbandwidth of the BS may be adjusted. For example, a network/BS mayinform the UE of bandwidth adjustment. For example, the UE receiveinformation/configuration for bandwidth adjustment from the network/BS.In this case, the UE may perform bandwidth adjustment based on thereceived information/configuration. For example, the bandwidthadjustment may include an increase/decrease of the bandwidth, a positionchange of the bandwidth, or a change in subcarrier spacing of thebandwidth.

For example, the bandwidth may be decreased during a period in whichactivity is low to save power. For example, the position of thebandwidth may move in a frequency domain. For example, the position ofthe bandwidth may move in the frequency domain to increase schedulingflexibility. For example, the subcarrier spacing of the bandwidth may bechanged. For example, the subcarrier spacing of the bandwidth may bechanged to allow a different service. A subset of a total cell bandwidthof a cell may be called a bandwidth part (BWP). The BA may be performedwhen the BS/network configures the BWP to the UE and the BS/networkinforms the UE of the BWP currently in an active state among theconfigured BWPs.

For example, the BWP may be at least any one of an active BWP, aninitial BWP, and/or a default BWP. For example, the UE may not monitordownlink radio link quality in a DL BWP other than an active DL BWP on aprimary cell (PCell). For example, the UE may not receive PDCCH,physical downlink shared channel (PDSCH), or channel stateinformation-reference signal (CSI-RS) (excluding RRM) outside the activeDL BWP. For example, the UE may not trigger a channel state information(CSI) report for the inactive DL BWP. For example, the UE may nottransmit physical uplink control channel (PUCCH) or physical uplinkshared channel (PUSCH) outside an active UL BWP. For example, in adownlink case, the initial BWP may be given as a consecutive RB set fora remaining minimum system information (RMSI) control resource set(CORESET) (configured by physical broadcast channel (PBCH)). Forexample, in an uplink case, the initial BWP may be given by systeminformation block (SIB) for a random access procedure. For example, thedefault BWP may be configured by a higher layer. For example, an initialvalue of the default BWP may be an initial DL BWP. For energy saving, ifthe UE fails to detect downlink control information (DCI) during aspecific period, the UE may switch the active BWP of the UE to thedefault BWP.

Meanwhile, the BWP may be defined for SL. The same SL BWP may be used intransmission and reception. For example, a transmitting UE may transmitan SL channel or an SL signal on a specific BWP, and a receiving UE mayreceive the SL channel or the SL signal on the specific BWP. In alicensed carrier, the SL BWP may be defined separately from a Uu BWP,and the SL BWP may have configuration signaling separate from the UuBWP. For example, the UE may receive a configuration for the SL BWP fromthe BS/network. The SL BWP may be (pre-)configured in a carrier withrespect to an out-of-coverage NR V2X UE and an RRC_IDLE UE. For the UEin the RRC_CONNECTED mode, at least one SL BWP may be activated in thecarrier.

FIG. 7 shows an example of a BWP, based on an embodiment of the presentdisclosure. The embodiment of FIG. 7 may be combined with variousembodiments of the present disclosure. It is assumed in the embodimentof FIG. 7 that the number of BWPs is 3.

Referring to FIG. 7 , a common resource block (CRB) may be a carrierresource block numbered from one end of a carrier band to the other endthereof. In addition, the PRB may be a resource block numbered withineach BWP. A point A may indicate a common reference point for a resourceblock grid.

The BWP may be configured by a point A, an offset N^(start) _(BWP) fromthe point A, and a bandwidth N^(size) _(BWP). For example, the point Amay be an external reference point of a PRB of a carrier in which asubcarrier 0 of all numerologies (e.g., all numerologies supported by anetwork on that carrier) is aligned. For example, the offset may be aPRB interval between a lowest subcarrier and the point A in a givennumerology. For example, the bandwidth may be the number of PRBs in thegiven numerology.

Hereinafter, V2X or SL communication will be described.

FIG. 8 shows a radio protocol architecture for a SL communication, basedon an embodiment of the present disclosure. The embodiment of FIG. 8 maybe combined with various embodiments of the present disclosure. Morespecifically, FIG. 8(a) shows a user plane protocol stack, and FIG. 8(b)shows a control plane protocol stack.

Hereinafter, a sidelink synchronization signal (SLSS) andsynchronization information will be described.

The SLSS may include a primary sidelink synchronization signal (PSSS)and a secondary sidelink synchronization signal (SSSS), as anSL-specific sequence. The PSSS may be referred to as a sidelink primarysynchronization signal (S-PSS), and the SSSS may be referred to as asidelink secondary synchronization signal (S-SSS). For example,length-127 M-sequences may be used for the S-PSS, and length-127 goldsequences may be used for the S-SSS. For example, a UE may use the S-PSSfor initial signal detection and for synchronization acquisition. Forexample, the UE may use the S-PSS and the S-SSS for acquisition ofdetailed synchronization and for detection of a synchronization signalID.

A physical sidelink broadcast channel (PSBCH) may be a (broadcast)channel for transmitting default (system) information which must befirst known by the UE before SL signal transmission/reception. Forexample, the default information may be information related to SLSS, aduplex mode (DM), a time division duplex (TDD) uplink/downlink (UL/DL)configuration, information related to a resource pool, a type of anapplication related to the SLSS, a subframe offset, broadcastinformation, or the like. For example, for evaluation of PSBCHperformance, in NR V2X, a payload size of the PSBCH may be 56 bitsincluding 24-bit CRC.

The S-PSS, the S-SSS, and the PSBCH may be included in a block format(e.g., SL synchronization signal (SS)/PSBCH block, hereinafter,sidelink-synchronization signal block (S-SSB)) supporting periodicaltransmission. The S-SSB may have the same numerology (i.e., SCS and CPlength) as a physical sidelink control channel (PSCCH)/physical sidelinkshared channel (PSSCH) in a carrier, and a transmission bandwidth mayexist within a (pre-)configured sidelink (SL) BWP. For example, theS-SSB may have a bandwidth of 11 resource blocks (RBs). For example, thePSBCH may exist across 11 RBs. In addition, a frequency position of theS-SSB may be (pre-)configured. Accordingly, the UE does not have toperform hypothesis detection at frequency to discover the S-SSB in thecarrier.

FIG. 9 shows a UE performing V2X or SL communication, based on anembodiment of the present disclosure. The embodiment of FIG. 9 may becombined with various embodiments of the present disclosure.

Referring to FIG. 9 , in V2X or SL communication, the term ‘UE’ maygenerally imply a UE of a user. However, if a network equipment such asa BS transmits/receives a signal according to a communication schemebetween UEs, the BS may also be regarded as a sort of the UE. Forexample, a UE 1 may be a first apparatus 100, and a UE 2 may be a secondapparatus 200.

For example, the UE 1 may select a resource unit corresponding to aspecific resource in a resource pool which implies a set of series ofresources. In addition, the UE 1 may transmit an SL signal by using theresource unit. For example, a resource pool in which the UE 1 is capableof transmitting a signal may be configured to the UE 2 which is areceiving UE, and the signal of the UE 1 may be detected in the resourcepool.

Herein, if the UE 1 is within a connectivity range of the BS, the BS mayinform the UE 1 of the resource pool. Otherwise, if the UE 1 is out ofthe connectivity range of the BS, another UE may inform the UE 1 of theresource pool, or the UE 1 may use a pre-configured resource pool.

In general, the resource pool may be configured in unit of a pluralityof resources, and each UE may select a unit of one or a plurality ofresources to use it in SL signal transmission thereof.

Hereinafter, resource allocation in SL will be described.

FIG. 10 shows a procedure of performing V2X or SL communication by a UEbased on a transmission mode, based on an embodiment of the presentdisclosure. The embodiment of FIG. 10 may be combined with variousembodiments of the present disclosure. In various embodiments of thepresent disclosure, the transmission mode may be called a mode or aresource allocation mode. Hereinafter, for convenience of explanation,in LTE, the transmission mode may be called an LTE transmission mode. InNR, the transmission mode may be called an NR resource allocation mode.

For example, FIG. 10(a) shows a UE operation related to an LTEtransmission mode 1 or an LTE transmission mode 3. Alternatively, forexample, FIG. 10(a) shows a UE operation related to an NR resourceallocation mode 1. For example, the LTE transmission mode 1 may beapplied to general SL communication, and the LTE transmission mode 3 maybe applied to V2X communication.

For example. FIG. 10(b) shows a UE operation related to an LTEtransmission mode 2 or an LTE transmission mode 4. Alternatively, forexample, FIG. 10(b) shows a UE operation related to an NR resourceallocation mode 2.

Referring to FIG. 10(a), in the LTE transmission mode 1, the LTEtransmission mode 3, or the NR resource allocation mode 1, a BS mayschedule an SL resource to be used by the UE for SL transmission. Forexample, the BS may perform resource scheduling to a UE 1 through aPDCCH (more specifically, downlink control information (DCI)), and theUE 1 may perform V2X or SL communication with respect to a UE 2according to the resource scheduling. For example, the UE 1 may transmita sidelink control information (SCI) to the UE 2 through a physicalsidelink control channel (PSCCH), and thereafter transmit data based onthe SCI to the UE 2 through a physical sidelink shared channel (PSSCH).

Referring to FIG. 10(b), in the LTE transmission mode 2, the LTEtransmission mode 4, or the NR resource allocation mode 2, the UE maydetermine an SL transmission resource within an SL resource configuredby a BS/network or a pre-configured SL resource. For example, theconfigured SL resource or the pre-configured SL resource may be aresource pool. For example, the UE may autonomously select or schedule aresource for SL transmission. For example, the UE may perform SLcommunication by autonomously selecting a resource within a configuredresource pool. For example, the UE may autonomously select a resourcewithin a selective window by performing a sensing and resource(re)selection procedure. For example, the sensing may be performed inunit of subchannels. In addition, the UE 1 which has autonomouslyselected the resource within the resource pool may transmit the SCI tothe UE 2 through a PSCCH, and thereafter may transmit data based on theSCI to the UE 2 through a PSSCH.

FIG. 11 shows three cast types, based on an embodiment of the presentdisclosure. The embodiment of FIG. 11 may be combined with variousembodiments of the present disclosure. Specifically. FIG. 11(a) showsbroadcast-type SL communication, FIG. 11(b) shows unicast type-SLcommunication, and FIG. 11(c) shows groupcast-type SL communication. Incase of the unicast-type SL communication, a UE may perform one-to-onecommunication with respect to another UE. In case of the groupcast-typeSL transmission, the UE may perform SL communication with respect to oneor more UEs in a group to which the UE belongs. In various embodimentsof the present disclosure, SL groupcast communication may be replacedwith SL multicast communication, SL one-to-many communication, or thelike.

Hereinafter, a hybrid automatic repeat request (HARQ) procedure will bedescribed.

An error compensation scheme is used to secure communicationreliability. Examples of the error compensation scheme may include aforward error correction (FEC) scheme and an automatic repeat request(ARQ) scheme. In the FEC scheme, errors in a receiving end are correctedby attaching an extra error correction code to information bits. The FECscheme has an advantage in that time delay is small and no informationis additionally exchanged between a transmitting end and the receivingend but also has a disadvantage in that system efficiency deterioratesin a good channel environment. The ARQ scheme has an advantage in thattransmission reliability can be increased but also has a disadvantage inthat a time delay occurs and system efficiency deteriorates in a poorchannel environment.

A hybrid automatic repeat request (HARQ) scheme is a combination of theFEC scheme and the ARQ scheme. In the HARQ scheme, it is determinedwhether an unrecoverable error is included in data received by aphysical layer, and retransmission is requested upon detecting theerror, thereby improving performance.

In case of SL unicast and groupcast, HARQ feedback and HARQ combining inthe physical layer may be supported. For example, when a receiving UEoperates in a resource allocation mode 1 or 2, the receiving UE mayreceive the PSSCH from a transmitting UE, and the receiving UE maytransmit HARQ feedback for the PSSCH to the transmitting UE by using asidelink feedback control information (SFCI) format through a physicalsidelink feedback channel (PSFCH).

For example, the SL HARQ feedback may be enabled for unicast. In thiscase, in a non-code block group (non-CBG) operation, if the receiving UEdecodes a PSCCH of which a target is the receiving UE and if thereceiving UE successfully decodes a transport block related to thePSCCH, the receiving UE may generate HARQ-ACK. In addition, thereceiving UE may transmit the HARQ-ACK to the transmitting UE.Otherwise, if the receiving UE cannot successfully decode the transportblock after decoding the PSCCH of which the target is the receiving UE,the receiving UE may generate the HARQ-NACK. In addition, the receivingUE may transmit HARQ-NACK to the transmitting UE.

For example, the SL HARQ feedback may be enabled for groupcast. Forexample, in the non-CBG operation, two HARQ feedback options may besupported for groupcast.

-   -   (1) Groupcast option 1: After the receiving UE decodes the PSCCH        of which the target is the receiving UE, if the receiving UE        fails in decoding of a transport block related to the PSCCH, the        receiving UE may transmit HARQ-NACK to the transmitting UE        through a PSFCH. Otherwise, if the receiving UE decodes the        PSCCH of which the target is the receiving UE and if the        receiving UE successfully decodes the transport block related to        the PSCCH, the receiving UE may not transmit the HARQ-ACK to the        transmitting UE.    -   (2) Groupcast option 2: After the receiving UE decodes the PSCCH        of which the target is the receiving UE, if the receiving UE        fails in decoding of the transport block related to the PSCCH,        the receiving UE may transmit HARQ-NACK to the transmitting UE        through the PSFCH. In addition, if the receiving UE decodes the        PSCCH of which the target is the receiving UE and if the        receiving UE successfully decodes the transport block related to        the PSCCH, the receiving UE may transmit the HARQ-ACK to the        transmitting UE through the PSFCH.

For example, if the groupcast option 1 is used in the SL HARQ feedback,all UEs performing groupcast communication may share a PSFCH resource.For example, UEs belonging to the same group may transmit HARQ feedbackby using the same PSFCH resource.

For example, if the groupcast option 2 is used in the SL HARQ feedback,each UE performing groupcast communication may use a different PSFCHresource for HARQ feedback transmission. For example, UEs belonging tothe same group may transmit HARQ feedback by using different PSFCHresources.

For example, when the SL HARQ feedback is enabled for groupcast, thereceiving UE may determine whether to transmit the HARQ feedback to thetransmitting UE based on a transmission-reception (TX-RX) distanceand/or RSRP.

For example, in the groupcast option 1, in case of the TX-RXdistance-based HARQ feedback, if the TX-RX distance is less than orequal to a communication range requirement, the receiving UE maytransmit HARQ feedback for the PSSCH to the transmitting UE. Otherwise,if the TX-RX distance is greater than the communication rangerequirement, the receiving UE may not transmit the HARQ feedback for thePSSCH to the transmitting UE. For example, the transmitting UE mayinform the receiving UE of a location of the transmitting UE through SCIrelated to the PSSCH. For example, the SCI related to the PSSCH may besecond SCI. For example, the receiving UE may estimate or obtain theTX-RX distance based on a location of the receiving UE and the locationof the transmitting UE. For example, the receiving UE may decode the SCIrelated to the PSSCH and thus may know the communication rangerequirement used in the PSSCH.

For example, in case of the resource allocation mode 1, a time (offset)between the PSFCH and the PSSCH may be configured or pre-configured. Incase of unicast and groupcast, if retransmission is necessary on SL,this may be indicated to a BS by an in-coverage UE which uses the PUCCH.The transmitting UE may transmit an indication to a serving BS of thetransmitting UE in a form of scheduling request (SR)/buffer statusreport (BSR), not a form of HARQ ACK/NACK. In addition, even if the BSdoes not receive the indication, the BS may schedule an SLretransmission resource to the UE. For example, in case of the resourceallocation mode 2, a time (offset) between the PSFCH and the PSSCH maybe configured or pre-configured.

For example, from a perspective of UE transmission in a carrier, TDMbetween the PSCCH/PSSCH and the PSFCH may be allowed for a PSFCH formatfor SL in a slot. For example, a sequence-based PSFCH format having asingle symbol may be supported. Herein, the single symbol may not an AGCduration. For example, the sequence-based PSFCH format may be applied tounicast and groupcast.

For example, in a slot related to a resource pool, a PSFCH resource maybe configured periodically as N slot durations, or may bepre-configured. For example, N may be configured as one or more valuesgreater than or equal to 1. For example, N may be 1, 2, or 4. Forexample, HARQ feedback for transmission in a specific resource pool maybe transmitted only through a PSFCH on the specific resource pool.

For example, if the transmitting UE transmits the PSSCH to the receivingUE across a slot #X to a slot #N, the receiving UE may transmit HARQfeedback for the PSSCH to the transmitting UE in a slot #(N+A). Forexample, the slot #(N+A) may include a PSFCH resource. Herein, forexample, A may be a smallest integer greater than or equal to K. Forexample, K may be the number of logical slots. In this case, K may bethe number of slots in a resource pool. Alternatively, for example, Kmay be the number of physical slots. In this case, K may be the numberof slots inside or outside the resource pool.

For example, if the receiving UE transmits HARQ feedback on a PSFCHresource in response to one PSSCH transmitted by the transmitting UE tothe receiving UE, the receiving UE may determine a frequency domainand/or code domain of the PSFCH resource based on an implicit mechanismin a configured resource pool. For example, the receiving UE maydetermine the frequency domain and/or code domain of the PSFCH resource,based on at least one of a slot index related to PSCCH/PSSCH/PSFCH, asub-channel related to PSCCH/PSSCH, and/or an identifier for identifyingeach receiving UE in a group for HARQ feedback based on the groupcastoption 2. Additionally/alternatively, for example, the receiving UE maydetermine the frequency domain and/or code domain of the PSFCH resource,based on at least one of SL RSRP, SINR, L1 source ID, and/or locationinformation.

For example, if HARQ feedback transmission through the PSFCH of the UEand HARQ feedback reception through the PSFCH overlap, the UE may selectany one of HARQ feedback transmission through the PSFCH and HARQfeedback reception through the PSFCH based on a priority rule. Forexample, the priority rule may be based on at least priority indicationof the related PSCCH/PSSCH.

For example, if HARQ feedback transmission of a UE through a PSFCH for aplurality of UEs overlaps, the UE may select specific HARQ feedbacktransmission based on the priority rule. For example, the priority rulemay be based on at least priority indication of the related PSCCH/PSSCH.

Meanwhile, if the groupcast option 1 is used for sidelink groupcasttransmission, a plurality of receiving UEs (e.g., all receiving UEs orsome receiving UEs in a group) may share a PSFCH resource to transmitHARQ feedback. On the other hand, if the groupcast option 2 is used forsidelink groupcast transmission, a plurality of receiving UEs (e.g.,each receiving UE in a group) may transmit HARQ ACK or HARQ NACK byusing separate PSFCH resources. For example, each of PSFCH resources maybe mapped to a time domain resource, a frequency domain resource, and acode domain resource.

Meanwhile, all or a part of resources through which a plurality ofPSSCHs are transmitted may overlap. For example, resources through whicha plurality of PSSCHs are transmitted may completely or partiallyoverlap each other on a frequency domain. For example, resources throughwhich a plurality of PSSCHs are transmitted may completely or partiallyoverlap each other on a time domain. For example, resources throughwhich a plurality of PSSCHs are transmitted may completely or partiallyoverlap each other on a code domain. If all or a part of resources fortransmitting a plurality of PSSCHs overlap, PSFCH resources for eachPSSCH may need to be distinguished.

Meanwhile, PSSCHs transmitted through different resources may correspondto different transmitting UEs and/or receiving UEs. and PSFCHtransmissions corresponding thereto may also occur from different UEs.For example, different transmitting UEs may transmit PSSCHs throughdifferent resources, and different transmitting UEs may receive PSFCHscorresponding to the PSSCHs from different UEs. In the above case, ingeneral, transmit power of the PSFCHs may be different. Therefore, if aplurality of PSFCH resources are multiplexed in a code domain (i.e.,code-domain multiplexing (CDM)), a problem (hereinafter, a near-farproblem) in which the UE cannot detect a specific PSFCH signal may occurdue to a large difference in receive power at the PSFCH receiving end.For example, the case in which a plurality of PSFCH resources aremultiplexed in the code domain may mean a case in which a plurality ofPSFCH resources overlapping in time and frequency resources aretransmitted by using different codes.

FIG. 12 shows a diagram for explaining a problem in that a UE cannotdetect a specific PSFCH signal due to a large difference in receivepower at a PSFCH receiving end, based on an embodiment of the presentdisclosure. The embodiment of FIG. 12 may be combined with variousembodiments of the present disclosure.

Referring to FIG. 12 , if a PSFCH transmitted by a UE2 to a UE1 and aPSFCH transmitted by a UE4 to a UE3 are CDM, that is, if the PSFCH fromthe UE2 and the PSFCH from the UE4 are transmitted on overlapping timeand frequency resources by using different codes, the UE3 cannot detectthe PSFCH transmitted by the UE4 if receive power of the PSFCHtransmitted by the UE2 is greater than receive power of the PSFCHtransmitted by the UE4 by a certain level in terms of the UE3.

FIG. 13 shows an example in which a plurality of PSFCHs are CDM, basedon an embodiment of the present disclosure. The embodiment of FIG. 13may be combined with various embodiments of the present disclosure.

Referring to FIG. 13 , a PSFCH corresponding to a PSSCH transmitted froma UE1 to a UE2 and a PSFCH corresponding to a PSSCH transmitted from aUE3 to a UE4 may be CDM.

Furthermore, if a plurality of PSFCH resources are adjacent on afrequency domain, an interference problem (hereinafter, an inter-bandemission (IBE) problem) may occur. IBE may mean that transmit power ofsignal(s) transmitted by a UE is emitted in a band other than anintended frequency band, thereby reducing reception quality byinterfering with other signals being transmitted in a frequency band notused by the UE. For example, if a PSFCH resource #1 and a PSFCH resource#2 are adjacent on a frequency domain, HARQ feedback received throughthe PSFCH resource #1 and HARQ feedback received through the PSFCHresource #2 by the UE may interfere with each other. Therefore, due tothe above IBE problem, the UE may fail to receive HARQ feedback.

Meanwhile, PSFCH resources for PSSCHs transmitted in a plurality ofslots may occur in the same slot. In this case, considering latencyrequirements and performance of the corresponding service, it may beinefficient for a UE to transmit a PSFCH corresponding to a PSSCHtransmitted in a slot far in time from a slot in which PSFCH resourcesexists. For example, if a first UE transmits data for service(s)requiring low latency to a second UE through a specific PSSCH resource,it may be unnecessary for the second UE to transmit a PSFCH to the firstUE in a slot far in time from a slot in which the specific PSSCHresource exists. In this case, in order to satisfy latency requirements,the UE receiving the PSSCH may omit transmission of the PSFCH. That is,it may be efficient for the UE to preferentially secure a PSFCH resourcecorresponding to a resource for a PSSCH transmitted in a slot close intime to a slot in which PSFCH resources exists.

Meanwhile, in the case of groupcast in the next-generation system, aplurality of receiving UE which has received a PSCCH may transmit HARQfeedback for the same PSSCH, respectively. In this case, there may be aplurality of PSFCH resources corresponding to a specific PSSCH, and eachof PSFCH resources may be distinguished.

On the other hand, in the case of groupcast in the next-generationsystem, a plurality of receiving UEs which has received a PSSCH mayshare a PSFCH resource for HARQ feedback for the same PSSCH. If atransmitting UE receives HARQ feedback for a first PSSCH from at leastone of a plurality of receiving UEs through a first PSFCH resource afterthe transmitting UE transmits the first PSSCH to the plurality ofreceiving UEs, and the transmitting UE receives HARQ feedback for asecond PSSCH from a specific receiving UE through a second PSFCHresource after the transmitting UE transmits the second PSSCH to thespecific receiving UE, receive power for the first PSFCH of thetransmitting UE may be relatively greater than receive power for thesecond PSFCH. Therefore, a serious IBE problem between PSFCH resourcesmay occur.

Hereinafter, based on an embodiment of the present disclosure, a methodfor efficiently allocating PSFCH resource(s) and an apparatus supportingthe same are proposed. In various embodiments of the present disclosure,the operation order of the UE may be changed. For example, in theembodiment of FIG. 14 , S1430 may be performed before S1410.

FIG. 14 shows a procedure for a transmitting UE to select/determinePSFCH resource(s), based on an embodiment of the present disclosure. Theembodiment of FIG. 14 may be combined with various embodiments of thepresent disclosure.

Referring to FIG. 14 , in step S1410, the transmitting UE mayselect/determine/allocate a PSFCH resource set. For example, thetransmitting UE may select/determine/allocate the PSFCH resource setbased on sub-channel(s) allocated for a PSSCH resource and/or a slot inwhich a PSSCH is transmitted and/or information related to PSSCHtransmission. For example, the information related to PSSCH transmissionmay include at least one of DMRS sequence(s) or an ID (e.g., source ID)of the transmitting UE. In the present disclosure, a sub-channel mayinclude one or more resource blocks (RBs).

For example, the transmitting UE may select/determine the PSFCH resourceset based on the DMRS sequence(s) used for PSSCH transmission orparameter value(s) for generating the DMRS sequence(s). For example, thetransmitting UE may select/determine the PSFCH resource set based on theDMRS sequence(s) used for PSCCH transmission related to the PSSCH orparameter value(s) for generating the DMRS sequence(s). For example, thetransmitting UE may select/determine the PSFCH resource set based on amodulo value of the ID (e.g., source ID) of the transmitting UE. Throughthis, even if a plurality of PSSCHs overlap between sub-channels, thetransmitting UE can distinguish PSFCH resource sets related to theplurality of PSSCHs.

FIG. 15 shows a method for determining a PSFCH resource set, based on anembodiment of the present disclosure. The embodiment of FIG. 15 may becombined with various embodiments of the present disclosure.

Referring to FIG. 15 , the transmitting UE may select/determine thePSFCH resource set based on at least one of sub-channel(s) allocated fora PSSCH resource, a slot in which a PSSCH is transmitted, or informationrelated to PSSCH transmission.

Referring back to FIG. 14 , in step S1420, the transmitting UE mayselect/determine/allocate a specific PSFCH resource in the PSFCHresource set based on a cast type and/or an HARQ feedback method/option.For example, the cast type may be unicast or groupcast.

For example, the HARQ feedback method/option may be divided into twotypes. According to the first HARQ feedback method/option, thetransmitting UE may transmit a PSSCH to a plurality of receiving UEs ingroupcast, and receiving UE(s) may transmit HARQ feedback related to thePSSCH to the transmitting UE through a common PSFCH resource. In thiscase, the receiving UE(s) may transmit NACK to the transmitting UEthrough the common PSFCH resource only if decoding of the PSSCH fails.On the other hand, if the receiving UE(s) succeeds in decoding thePSSCH, the receiving UE(s) may not transmit ACK to the transmitting UE.

According to the second HARQ feedback method/option, the transmitting UEmay transmit a PSSCH to a plurality of receiving UEs in groupcast, andreceiving UE(s) may transmit HARQ feedback related to the PSSCH to thetransmitting UE through different PSFCH resources. In this case, ifdecoding of the PSSCH fails, the receiving UE(s) may transmit NACK tothe transmitting UE through individual PSFCH resource(s). In addition,if the receiving UE(s) succeeds in decoding the PSSCH, the receivingUE(s) may transmit ACK to the transmitting UE through individual PSFCHresource(s).

In the present disclosure, for convenience of description, a PSFCHresource for unicast may be referred to as a unicast PSFCH resource, anda PSFCH resource related to the first HARQ feedback method/option ingroupcast may be referred to as a common PSFCH resource, and a PSFCHresource related to the second HARQ feedback method/option in groupcastmay be referred to as an individual PSFCH resource.

Based on an embodiment of the present disclosure, in the case of unicastand in the case of groupcast in which a PSFCH resource are shared amonga plurality of PSSCH receiving UEs, the transmitting UE mayselect/determine different PSFCH resources. In addition, thetransmitting UE may secure N RBs between a unicast PSFCH resource and acommon PSFCH resource. For example, N may be a positive integer. Thatis, one or more RB intervals may be secured between the unicast PSFCHresource and the common PSFCH resource. For example, a base station mayconfigure the RB interval or an offset value for designating the RBlocation for the PSFCH resource to the transmitting UE for each resourcepool. For example, the base station may pre-configure the RB interval oran offset value for designating the RB location for the PSFCH resourceto the transmitting UE for each resource pool. For example, the RBinterval or an offset value for designating the RB location for thePSFCH resource may be predefined in the transmitting UE for eachresource pool.

FIG. 16 shows a method for securing one or more RB intervals between aunicast PSFCH and a common PSFCH, based on an embodiment of the presentdisclosure. The embodiment of FIG. 16 may be combined with variousembodiments of the present disclosure.

Referring to FIG. 16 , an interval N RBs may be secured between theunicast PSFCH and the common PSFCH, and thus the IBE problem betweenPSFCH resources may be alleviated.

Based on an embodiment of the present disclosure, in the case ofunicast, the transmitting UE may select/determine different unicastPSFCH resources for each unicast session. For example, if thetransmitting UE establishes unicast sessions with a plurality ofdifferent receiving UEs, the transmitting UE may select/determinedifferent unicast PSFCH resources for each unicast session.

FIG. 17 shows a method in which different unicast PSFCH resources areselected/determined for each unicast session, based on an embodiment ofthe present disclosure. The embodiment of FIG. 17 may be combined withvarious embodiments of the present disclosure.

Referring to FIG. 17 , the transmitting UE may establish unicastsessions with a first UE, a second UE and a third UE, and may transmit afirst PSSCH, a second PSSCH and a third PSSCH to the first UE, thesecond UE and the third UE, respectively. In this case, the transmittingUE may select/determine different unicast PSFCH resources for eachunicast session. That is, the transmitting UE may differentlyselect/determine a PSFCH resource for the first UE, a PSFCH resource forthe second UE, and a PSFCH resource for the third UE.

Based on an embodiment of the present disclosure, if PSFCH resources aredivided between PSSCH receiving UEs in groupcast, the transmitting UEmay receive HARQ feedback through a plurality of PSFCH resources. In thePSFCH resource set, N RB intervals may exist between a PSFCH resourcecorresponding to unicast and a PSFCH resource corresponding to groupcastin which PSFCH resources are divided between a plurality of PSSCHreceiving UEs. That is, the transmitting UE may receive or havedifferent offsets between PSFCH resource sets based on a cast typeand/or whether a PSFCH resource are shared.

Referring back to FIG. 14 , in step S1430, the transmitting UE maytransmit the PSSCH and/or the PSCCH to the receiving UE.

In step S1440, the transmitting UE may receive HARQ feedback for thePSSCH and/or the PSCCH from the receiving UE through a specific PSFCHresource in the PSFCH resource set. For example, the specific PSFCHresource may be determined by the transmitting UE based on the cast typeand/or the HARQ feedback method/option.

FIG. 18 shows a procedure for a receiving UE to select/determine PSFCHresource(s), based on an embodiment of the present disclosure. Theembodiment of FIG. 18 may be combined with various embodiments of thepresent disclosure.

Referring to FIG. 18 , in step S1810, the receiving UE mayselect/determine/allocate a PSFCH resource set. For example, thereceiving UE may select/determine/allocate the PSFCH resource set basedon sub-channel(s) allocated for a PSSCH resource and/or a slot in whicha PSSCH is transmitted and/or information related to PSSCH transmission.For example, the information related to PSSCH transmission may includeat least one of DMRS sequence(s) or an ID (e.g., source ID) of thetransmitting UE. A method for the receiving UE to select/determine thePSFCH resource set may be the same as the method for the transmitting UEto select/determine the PSFCH resource set.

In step S1820, the receiving UE may select/determine/allocate a specificPSFCH resource in the PSFCH resource set based on the cast type and/orthe HARQ feedback method/option. A method for the receiving UE toselect/determine the specific PSFCH resource in the PSFCH resource setmay be the same as the method for the transmitting UE toselect/determine the specific PSFCH resource in the PSFCH resource set.If each of PSFCH resources is distinguished between PSSCH receiving UEsin groupcast, each receiving UE may select a PSFCH resource based onreceiving UE information (e.g., an identifier provided by a higher layeror an ID (e.g., source ID) of the receiving UE).

In step S1830, the receiving UE may receive the PSSCH and/or the PSCCHfrom the transmitting UE.

In step S1840, the receiving UE may transmit HARQ feedback for the PSSCHand/or the PSCCH to the transmitting UE through the specific PSFCHresource in the PSFCH resource set. For example, the specific PSFCHresource may be determined by the receiving UE based on the cast typeand/or the HARQ feedback method/option.

FIG. 19 shows a procedure for a transmitting UE to determine PSFCHresource(s), based on an embodiment of the present disclosure. Theembodiment of FIG. 19 may be combined with various embodiments of thepresent disclosure.

Referring to FIG. 19 , in step S1910, the transmitting UE maydetermine/select/allocate a PSFCH resource. For example, thetransmitting UE may select the PSFCH resource to be used for HARQfeedback, based on at least one of a slot corresponding to PSCCHtransmission and/or PSSCH transmission, sub-channel(s) corresponding toPSCCH transmission and/or PSSCH transmission, RB(s) corresponding toPSCCH transmission and/or PSSCH transmission, a cast type, a HARQfeedback method/option, information related to a PSSCH transmitting UE,information related to PSSCH transmission, or information related to aPSSCH receiving UE. For example, the transmitting UE may select thePSFCH resource to be used for HARQ feedback, based on a slotcorresponding to PSSCH transmission, sub-channel(s) corresponding toPSSCH transmission, information related to a PSSCH transmitting UE, andinformation related to a PSSCH receiving UE. For example, theinformation related to the PSSCH receiving UE may be determined based onthe cast type and/or the HARQ feedback method/option. For example, theinformation related to the PSSCH transmitting UE may be information on aUE transmitting the PSSCH (e.g., a source ID of the transmitting UE).For example, the information related to the PSSCH receiving UE may beinformation on a UE receiving the PSSCH (e.g., an identifier provided bya higher layer or a source ID of the receiving UE). For example, theinformation related to PSSCH transmission may include at least one ofDMRS sequence(s) used for PSSCH transmission or parameter(s) forgenerating the DMRS sequence(s), or DMRS sequence(s) used for PSCCHtransmission corresponding to the PSSCH or parameter(s) for generatingthe DMRS sequence(s).

For example, the PSFCH resource may correspond to a combination of aresource block (RB) and/or a code domain resource. For example, asub-channel may include one or more RBs. For example, the cast type maybe unicast or groupcast. For example, the HARQ feedback method/optionmay be divided into two types. According to the first HARQ feedbackmethod/option, the transmitting UE may transmit a PSSCH to a pluralityof receiving UEs in groupcast, and receiving UE(s) may transmit HARQfeedback related to the PSSCH to the transmitting UE through a commonPSFCH resource. In this case, the receiving UE(s) may transmit NACK tothe transmitting UE through the common PSFCH resource only if decodingof the PSSCH fails. On the other hand, if the receiving UE(s) succeedsin decoding the PSSCH, the receiving UE(s) may not transmit ACK to thetransmitting UE. According to the second HARQ feedback method/option,the transmitting UE may transmit a PSSCH to a plurality of receiving UEsin groupcast, and receiving UE(s) may transmit HARQ feedback related tothe PSSCH to the transmitting UE through different PSFCH resources.

Meanwhile, a plurality of transmitting UEs may transmit a plurality ofPSSCHs having different combinations of sub-channel(s) and a slot to aplurality of receiving UEs, respectively. In addition, the plurality ofreceiving UEs may transmit a plurality of PSFCHs corresponding to theplurality of PSSCHs to the plurality of transmitting UEs. In this case,since receive power of the plurality of PSFCHs may be greatly differentfrom the perspective of the plurality of transmitting UEs, an inter-bandemission (IBE) problem may occur. Accordingly, in the above situation,the transmitting UE may secure a plurality of RB gaps between theplurality of PSFCH resources in consideration of inter-band emission(IBE) between the plurality of PSFCHs corresponding to the plurality ofPSSCHs.

FIG. 20 shows a case in which N RB intervals exist between a pluralityof PSFCH resources, based on an embodiment of the present disclosure.The embodiment of FIG. 20 may be combined with various embodiments ofthe present disclosure.

For example, as in the embodiment of FIG. 20 , in the case of aplurality of PSFCH resources related to a plurality of PSSCHs (i.e.,PSSCH #1 and PSSCH #2) transmitted in the same slot and differentsub-channels, N RB intervals may exist between a plurality of PSFCHresources. For example, N may be a positive integer.

FIG. 21 shows a case in which N RB intervals exist between a pluralityof PSFCH resources, based on an embodiment of the present disclosure.The embodiment of FIG. 21 may be combined with various embodiments ofthe present disclosure.

For example, as in the embodiment of FIG. 21 , in the case of aplurality of PSFCH resources related to a plurality of PSSCHs (i.e.,PSSCH #1 to PSSCH #3) transmitted in the same sub-channel and differentslots, N RB intervals may exist between a plurality of PSFCH resources.For example, N may be a positive integer.

Specifically, for example, PSFCH resources according to the change ofthe two parameters may have a hierarchical structure. For example, thetwo parameters may be slot-related information and sub-channel-relatedinformation.

For example, if an RB interval between a plurality of PSFCH resourcesrelated to a plurality of PSSCHs transmitted in the same slot anddifferent sub-channels is N, and an RB interval between a plurality ofPSFCH resources related to a plurality of PSSCHs transmitted in the samesub-channel and different slots is M, a value of N may be expressed as avalue of M and the number of slots in a HARQ-related set. For example, avalue of N may be determined or derived based on a value of M and thenumber of slots in the HARQ-related set. In the present disclosure, theHARQ-related set may be a set of slots for PSCCHs and/or PSSCHs relatedto PSFCHs that can be transmitted in the same slot. If a value of N isexpressed as a value of M and the number of slots in the HARQ-relatedset, a large RB interval between a plurality of PSFCH resources may bemaintained in case some slots in the HARQ-related set are used for PSSCHtransmission or in case PSFCH resources are used for PSSCH transmissionof some slots. Therefore, in case the transmitting UE receives HARQfeedback through a plurality of PSFCH resources, the IBE problem can begreatly alleviated.

Alternatively, for example, if an RB interval between a plurality ofPSFCH resources related to a plurality of PSSCHs transmitted in the sameslot and different sub-channels is N. and an RB interval between aplurality of PSFCH resources related to a plurality of PSSCHstransmitted in the same sub-channel and different slots is M, a value ofM may be expressed as a value of N and the number of sub-channelsavailable for PSSCH transmission. For example, a value of M may bedetermined or derived based on a value of N and the number ofsub-channels available for PSSCH transmission. Specifically, forexample, the transmitting UE may relatively center a PSFCH resource setcorresponding to a specific slot in a resource pool by using an RBoffset, etc. If a value of M is expressed as a value of N and the numberof sub-channels available for PSSCH transmission, the transmitting UEmay set/configure an RB gap above and/or below an RB set in which PSFCHresource(s) is located, in case the frequency of use of PSFCH resourcesrelated to a PSSCH actually transmitted in a specific slot is high.Accordingly, emission from different resource pools or Uu links may bealleviated.

Meanwhile, different PSSCH transmissions may collide in a specificsub-channel and a specific slot. For example, if one transmitting UEtransmits a plurality of PSSCHs overlapping in time and frequencyresource(s) through spatial multiplexing, different PSSCH transmissionsmay collide in a specific sub-channel and/or a specific slot. Forexample, if a plurality of transmitting UEs transmit a plurality ofPSSCHs overlapping in time and frequency resource(s) (e.g., if adistance between UEs transmitting PSSCHs is large (i.e., a hidden nodeproblem)), different PSSCH transmissions may collide in a specificsub-channel and/or a specific slot. If a receiving UE can distinguishdifferent PSSCHs transmitted from transmitting UE(s), it may also berequired to separate PSFCH resources related to the plurality of PSSCHs.For example, the plurality of PSSCHs may be transmitted by onetransmitting UE. Alternatively, for example, the plurality of PSSCHs maybe transmitted by a plurality of transmitting UEs, respectively. Forexample, if sub-channels through which a plurality of PSCCHs related tothe plurality of PSSCHs are transmitted are different and/or if DMRSsequences for a plurality of PSCCHs or parameters for generating theDMRS sequences are different and/or if DMRS sequences for a plurality ofPSSCHs or parameters for generating the DMRS sequences are differentand/or all or part of source IDs is different, the receiving UE maydistinguish different PSSCHs sharing some resources with each other. Ingeneral, since each of different receiving UEs may receive each of aplurality of different PSCCHs, RB intervals may need to be secured asmuch as possible, in the case of PSFCH resources corresponding todifferent PSSCHs. This may be to alleviate the IBE problem in terms of aUE receiving HARQ feedback through PSFCHs, as described in detail above.That is, in the case of a plurality of PSSCHs transmitted by differenttransmitting UEs or by the same transmitting UE through a combination ofa specific slot and sub-channel(s), N RBs may exist between a pluralityof PSFCH resources corresponding to the plurality of PSSCHs. Forexample, N may be a positive integer.

Meanwhile, in the case of HARQ feedback in groupcast, each receiving UEreceiving the same PSSCH may allocate a PSFCH resource. If the receivingUE can perform power control when transmitting a PSFCH, and similarreceive power can be guaranteed at a PSSCH transmitting UE through thepower control, a Near-Far problem can be avoided or mitigated even ifCDM between the corresponding PSFCH resources is supported. In addition,even if PSFCH resources are allocated in adjacent RBs, the IBE problemcan be alleviated. On the other hand, if the receiving UE does notproperly perform power control for a PSFCH, the above-described problemmay occur. Accordingly, if the receiving UE cannot properly performpower control for a PSFCH, an interval N RBs between PSFCH resources mayneed to be secured. Accordingly, a multiplexing method between PSFCHresources for a plurality of receiving UEs for the same PSSCH ingroupcast may be configured differently, based on the power controlmethod for the PSFCH of the receiving UE and/or configuration(s) foreach resource pool. For example, a base station may configure orpre-configure the configuration(s) for each resource pool to the UE. Forexample, a base station may transmit the configuration(s) for eachresource pool to the UE.

Additionally, based on an embodiment of the present disclosure, a PSFCHresource selection/allocation scheme may be defined by Equation. Forexample, PSFCH resources may exist in a set of a combination of RB(s) inwhich PSFCH resources may exist and/or code domain resource(s), and eachPSFCH resource may have a different index based on the combination ofRB(s) and/or code domain resource(s).

For example, a virtual PSFCH resource index may be defined as inEquation 1 or Equation 2.

$\begin{matrix}{{{virtual}{PSFCH}{resource}{index}} = {{\left( {{specific}{subshannel}{corresponding}{to}{PSCCH}{or}{PSSCH}} \right) \times \left( {{first}{step}} \right)} + {\left( {{specific}{slot}{corresponding}{to}{PSSCH}} \right) \times \left( {{second}{}{step}} \right)} + {\left( {{information}{on}{PSSCH}{transmitting}{UE}} \right) \times \left( {{third}{}{step}} \right)} + {\left( {{information}{on}{PSSCH}{receiving}{UE}} \right) \times \left( {{fourth}{}{step}} \right)} + {index\_ offset}}} & \left\lbrack {{Equation}1} \right\rbrack\end{matrix}$ $\begin{matrix}{{{virtual}{PSFCH}{resource}{index}} = {{\left( {{specific}{slot}{corresponding}{to}{PSCCH}{or}{PSSCH}} \right) \times \left( {{first}{step}} \right)} + {\left( {{information}{on}{PSSCH}{transmitting}{UE}} \right) \times \left( {{second}{}{step}} \right)} + {\left( {{information}{on}{PSSCH}{receiving}{UE}} \right) \times \left( {{third}{}{step}} \right)} + {index\_ offset}}} & \left\lbrack {{Equation}2} \right\rbrack\end{matrix}$

In Equation 2, the index_offset may be a value derived/determined basedon a specific sub-channel corresponding to a PSCCH or a PSSCH. Forexample, the index_offset may be a value that changes based oninformation related to a specific sub-channel corresponding to a PSCCHor a PSSCH. For example, the index_offset may be configured such that aPSFCH resource coincides with a PSSCH resource related to the PSFCH in afrequency domain or a PSFCH resource is smaller than a PSSCH resourcerelated to the PSFCH in a frequency domain.

The virtual PSFCH resource may correspond to a logical resource. If thePSFCH resource selection scheme corresponds to a logical resource, aprocess of mapping the logical PSFCH resource to a physical resource maybe required. For example, the UE may map the virtual PSFCH resource tothe physical resource through a modulo function. In the above process,the size of the physical resource for the PSFCH may be smaller than thesize of the logical resource in terms of the frequency domain and/or thetime domain. For example, if the UE performs sidelink communication in anarrow band, the size of the physical resource for the PSFCH may besmaller than the size of the logical resource in terms of the frequencydomain and/or the time domain. For example, if the size of the physicalresource is smaller than the size of the logical resource, the UE mayallocate some PSFCH resources to overlap each other in the frequencydomain and/or the time domain. For example, if the size of the physicalresource is smaller than the size of the logical resource, the UE maynot allocate PSFCH resources to some virtual PSFCH resource indexes.

The mapping process to the physical resource may be performed in unitsof all logical resources or may be performed for a group of a specificlevel. For example, in the case of the level 1-group and the level2-group, overlapping of PSFCH resources between groups may not beallowed, and from the level 3-group, overlapping of some PSFCH resourcesmay be allowed depending on the size of the physical resource.

In the present disclosure, as an example of PSFCH resourceallocation/configuration/determination according to information relatedto a PSSCH receiving UE, PSFCH resources to be used/transmitted by UEsreceiving the same PSSCH are preferentially code division multiplexing(CDM), and PSFCH resource(s) may be allocated to adjacent RB(s) in casemore PSFCH resources are required.

In the present disclosure, as another example of PSFCH resourceallocation/configuration/determination according to information relatedto a PSSCH receiving UE, PSFCH resources to be used/transmitted by UEsreceiving the same PSSCH are allocated/configured/determined in the formof frequency division multiplexing (FDM) within a specific frequencyresource domain, and additional PSFCH resource(s) may beallocated/configured/determined in the form of CDM within the specificfrequency resource domain if PSFCH resource(s) are additionally requiredafter allocation/configuration/determination of PSFCH resources in theform of FDM. In this case, for example, the specific frequency resourcedomain may be specific sub-channel(s). In addition, for example, ifPSFCH resource(s) is additionally required after theallocation/configuration/determination of PSFCH resources in the form ofFDM and the allocation/configuration/determination of PSFCH resources inthe form of CDM, additional PSFCH resource(s) may beallocated/configured/determined in the form of FDM within a frequencyresource domain extended from the specific frequency resource domain. Inthis case, for example, the frequency resource domain extended comparedto the specific frequency resource domain may include at least one othersub-channel in addition to the specific sub-channel(s).

In the present disclosure, as another example of PSFCH resourceallocation/configuration/determination according to information relatedto a PSSCH receiving UE, PSFCH resources to be used/transmitted by UEsreceiving the same PSSCH are allocated/configured/determined in the formof FDM within a specific frequency resource domain, and additional PSFCHresource(s) may be allocated/configured/determined in the form of CDMwithin the specific frequency resource domain if PSFCH resource(s) areadditionally required after allocation/configuration/determination ofPSFCH resources in the form of FDM. In this case, for example, thespecific frequency resource domain may be a frequency resource domainincluding sub-channel(s) to which one or more PSSCHs corresponding tothe PSFCH resources are allocated. In the case of the above scheme,PSFCH resources may be allocated/configured/determined based on thenumber of sub-channels to which one or more PSSCHs corresponding to thePSFCH resources are allocated and/or the size/number of frequencyresource domains corresponding thereto.

In the present disclosure, as an example of a specific slotcorresponding to a PSSCH, indexing for slots in the HARQ-related set maybe set/configured in ascending order from a slot late in time to a slotearly in time. That is, among a plurality of slots in the HARQ-relatedset, a slot close to a PSFCH resource related to the HARQ-related setmay have a lower index value.

For example, a base station may configure or pre-configure the size ofeach step for the UE for each resource pool. Alternatively, the basestation may configure or pre-configure the size of a specific step forthe UE for each resource pool. In addition, the size of the remainingstep may be implicitly derived by the UE according to the size of othersteps and/or the range of value(s) that specific parameter(s) can have.For example, in Equation 1, the third step related to the information onthe PSSCH transmitting UE and/or the fourth step related to theinformation on the PSSCH receiving UE may be set/configured to a valuelarger than the first step and the second step. In this case, forexample, the information on the PSSCH transmitting UE may be an L1 layersource ID transmitted by the PSSCH transmitting UE to the PSSCHreceiving UE through a SCI, and the information on the PSSCH receivingUE may be a member ID assigned in unicast and/or groupcastcommunication. This configuration method may be advantageous to a methodof determining an RB value to which a PSFCH resource is allocated basedon a specific cyclic shift value and/or a specific base sequence value,and after increasing the cyclic shift value and/or the base sequencevalue, determining an RB value again based on the increased cyclic shiftvalue and the increased base sequence value. For example, contrary tothe above method, the third step and/or the fourth step may beset/configured to a value smaller than the first step and/or the secondstep. This configuration method may be advantageous to a method ofdetermining a cyclic shift value and/or a base sequence value based on aspecific RB value to which a PSFCH resource is allocated, and afterincreasing the RB value, determining a cyclic shift and/or a basesequence value again based on the increased RB value.

For example, when allocating/configuring/determining PSFCH resource(s),preferentially selecting/determining a PSFCH resource group based on astarting sub-channel of a PSSCH, and after selecting/determining thePSFCH resource group, a PSFCH resource sub-group may beconfigured/determined within the PSFCH resource group based on a slot inwhich the PSSCH is received. In this case, for example, PSFCH resourcesub-groups for different slots in which PSSCHs are received may beconfigured/determined in the form of FDM. As an example of the abovescheme, PSFCH resources may be allocated/configured/determined in theform of FDM in units of a PSFCH resource sub-group (first scheme). Forexample, assuming that each PSFCH resource sub-group includes N RBs, thefirst N RBs may correspond to a first PSSCH reception slot, and the nextN RBs may correspond to a second PSSCH reception slot. In this case, forexample, a value of the second step may be set/determined to a valueequal to the number of PSSCH reception slots or a value greater than thenumber of PSSCH reception slots. In addition, for example, if a schemein which PSFCH resources are allocated/configured/determined in the formof CDM is additionally considered in the first scheme, a value of thesecond step may be set/determined to a value equal to the number ofPSSCH reception slots or a value obtained by multiplying a value greaterthan the number of PSSCH reception slots by the number of cyclic shiftsper an RB. As another example of the above method, PSFCH resources maybe allocated/configured/determined in the form of FDM in units of an RBor an RB group (second scheme). For example, assuming that each PSFCHresource sub-group includes N RBs, a PSFCH resource corresponding to afirst PSSCH reception slot and a PSFCH resource corresponding to asecond PSSCH reception slot may be allocated/configured/determined inthe form that is sequentially repeated in units of 1 RB. In this case,for example, a value of the second step may be set/determined to a valuesmaller than the number of PSSCH reception slots. Specifically, forexample, a value of the second step may be set/determined to be in unitsof 1 RB, which is a value smaller than the number of PSSCH receptionslots. In addition, for example, if a scheme in which PSFCH resourcesare allocated/configured/determined in the form of CDM is additionallyconsidered in the second scheme, a value of the second step may beset/determined as a value obtained by multiplying a value smaller thanthe number of PSSCH reception slots by the number of cyclic shifts peran RB.

For example, PSFCH resources corresponding to PSSCHs transmitted in aplurality of slots may be allocated to the same slot. In this case,considering delay requirements and performance of services related todata transmitted through the PSSCHs, it may be inefficient for areceiving UE to transmit a PSFCH, corresponding to a PSSCH transmittedin a slot far away in a time domain from a slot to which a PSFCHresource is allocated, by using the slot to which the PSFCH resource isallocated. Alternatively, for example, if a first UE transmits data fora service requiring low latency to a second UE through a specific PSSCHresource, it may be unnecessary for the second UE to transmit a PSFCH tothe first UE in a slot to which a PSFCH resource is allocated faraway ina time domain from a slot to which the specific PSSCH resource isallocated. In this case, for example, in order to satisfy a latencyrequirement of the service related to data transmitted through thePSSCH, the receiving UE may omit or not perform transmission of thePSFCH in the slot to which the PSFCH resource is allocated far away inthe time domain from the slot in which the PSSCH is transmitted. Throughthis, it may be efficient for the receiving UE to preferentially securePSFCH resource(s) corresponding to PSSCH(s) transmitted in slot(s) thatis close in the time domain from a slot to which PSFCH resources areallocated. Meanwhile, for example, if PSFCH resources (e.g., frequencydomain resources and/or code domain resources) are insufficient, thereceiving UE may not preferentially allocate PSFCH resource(s)corresponding to a specific slot in which PSSCH(s) is transmitted. Inthis case, for example, the specific slot may be slot(s) close to a slotto which PSFCH resources are allocated or slot(s) far from a slot towhich PSFCH resources are allocated. Alternatively, for example, ifPSFCH resources (e.g., frequency domain resources and/or code domainresources) are insufficient, the receiving UE may equally reduce theallocation amount of PSFCH resources for each of a plurality of PSSCHtransmissions related to/corresponding to a slot to which PSFCHresources are allocated. Through this, the receiving UE can efficientlyoperate limited PSFCH resources.

For example, the index_offset value may be set differently based on aPSFCH format. That is, PSFCH resource sets may be distinguished fromeach other for each PSFCH format. For example, the PSFCH format mayinclude a sequence-based PSFCH format with one symbol, a PSFCH formatwith N symbols (e.g., N=2) in which a PSFCH format with one symbol isrepeated, a PUCCH format 2-based PSFCH format, and/or a PSFCH formatspanning all available symbols for sidelink in a slot. In this case, theUE may apply the index_offset value differently for each type of thePSFCH format.

For example, a plurality of HARQ-related sets may be configured in oneresource pool. For example, the UE may configure a plurality ofHARQ-related sets in one resource pool. That is, if each UE has adifferent processing time, and/or based on a service type and/or a casttype and/or a requirement (e.g., reliability and/or latency), a (minimumor maximum) time between a PSSCH transmission time and a PSFCHtransmission time may be configured differently, and in this case, theHARQ-related set may be configured for each (minimum or maximum) timebetween each PSSCH transmission time and each PSFCH transmission time.

For example, based on the processing time of the UE, the (minimum ormaximum) time between the PSSCH transmission time and the PSFCHtransmission time may be different, and in this case, the UE mayconfigure/set each HARQ-related set corresponding to the (minimum ormaximum) time between each PSSCH transmission time and each PSFCHtransmission time. Additionally/alternatively, for example, based on theservice type, the (minimum or maximum) time between the PSSCHtransmission time and the PSFCH transmission time may be different, andin this case, the UE may configure/set each HARQ-related setcorresponding to the (minimum or maximum) time between each PSSCHtransmission time and each PSFCH transmission time.Additionally/alternatively, based on the cast type, the (minimum ormaximum) time between the PSSCH transmission time and the PSFCHtransmission time may be different, and in this case, the UE mayconfigure/set each HARQ-related set corresponding to the (minimum ormaximum) time between each PSSCH transmission time and each PSFCHtransmission time. Additionally/alternatively, based on service-relatedrequirements (e.g., reliability and/or latency), the (minimum ormaximum) time between the PSSCH transmission time and the PSFCHtransmission time may be different, and in this case, the UE mayconfigure/set each HARQ-related set corresponding to the (minimum ormaximum) time between each PSSCH transmission time and each PSFCHtransmission time.

For example, for a plurality of HARQ-related sets configured in oneresource pool, one or more partial slots may be configured to overlap.Specifically, for example, the one or more partial slots may be includedin a first HARQ-related set among the plurality of HARQ-related sets,and may also be included in a second HARQ-related set different from thefirst HARQ-related set. Alternatively, for example, for a plurality ofHARQ related-sets configured in one resource pool, any slot may beconfigured not to overlap. Specifically, for example, slots included ina specific HARQ-related set among the plurality of HARQ-related sets maynot be included in the remaining HARQ related-sets except for thespecific HARQ-related set.

For example, the PSFCH resource set or the index_offset value may beconfigured or determined differently for each HARQ-related set. That is,PSFCH resource sets may be distinguished from each other for eachHARQ-related set. Herein, for example, the size of a HARQ codebook (orHARQ-ACK codebook) and/or the PSFCH format may be configured ordetermined differently for each HARQ-related set. In this case, forexample, if a receiving UE transmits HARQ feedback (e.g., ACK, NACK ordiscontinuous transmission (DTX)) for each of a plurality of PSSCHsand/or PSCCHs received from transmitting UE(s) based on PSFCHresource(s), a combination of HARQ feedback for each of the PSSCHsand/or the PSCCHs may be included in the configured/determined HARQcodebook (or HARQ-ACK codebook). In addition, for example, if thereceiving UE transmits HARQ feedback (e.g., ACK, NACK or DTX) for eachof a plurality of transport blocks (TBs) or code block groups (CBGs)received from transmitting UE(s) based on PSFCH resource(s), thereceiving UE may transmit a HARQ codebook (or HARQ-ACK codebook)including a plurality of HARQ feedback related information.Specifically, for example, in a situation in which PSFCH resources areinsufficient, the UE may preferentially allocate the PSFCH resource setto the HARQ-related set corresponding to a value in which the (minimumor maximum) time between the PSSCH transmission time and the PSFCHtransmission time is relatively small.

For example, the UE may share the PSFCH resource set with respect to theunion of slots included in a plurality of HARQ-related sets. Herein, forexample, if a specific slot exists in common in a plurality ofHARQ-related sets or if a specific slot is commonly included in aplurality of HARQ-related sets, the UE may set or determine the size ofa HARQ codebook (or HARQ-ACK codebook) used for HARQ feedbacktransmission for PSSCH and/or PSCCH transmission in the specific slot,based on the size of a HARQ codebook (or HARQ-ACK codebook) having alarge size value among a plurality of HARQ codebooks (or HARQ-ACKcodebooks) configured/determined for each of a plurality of HARQ-relatedsets. For example, if a specific slot exists in common in a plurality ofHARQ-related sets or if a specific slot is commonly included in aplurality of HARQ-related sets, the UE may set or determine the size ofa HARQ codebook (or HARQ-ACK codebook) used for HARQ feedbacktransmission for PSSCH and/or PSCCH transmission in the specific slotto/as a larger value among size values of a plurality of HARQ codebooks(or HARQ-ACK codebooks) related to each of a plurality of HARQ-relatedsets. Alternatively, for example, for the union of slots included in aplurality of HARQ-related sets, the UE may set or determine the size ofa HARQ codebook (or HARQ-ACK codebook) used for HARQ feedbacktransmission for PSSCH and/or PSCCH transmission in slots included inthe union identically or commonly.

For example, in the present disclosure, if a (virtual) PSFCH resourceindex value indicates an RB index, or if a (virtual) PSFCH resourceindex value is assigned/set/determined to a value corresponding to an RBindex, a process of separately setting/determining a cyclic shift valueand/or a base sequence value may be additionally required. For example,the cyclic shift value and/or the base sequence value may beset/determined based on a member ID value. In this case, for example,the member ID value may be set to a specific value in unicast and/orgroupcast option 1 communication. For example, the specific value may be0.

Referring back to FIG. 19 , in step S1920, the transmitting UE maytransmit the PSSCH and/or the PSCCH to the receiving UE.

In step S1930, the transmitting UE may receive HARQ feedback for thePSSCH and/or the PSCCH from the receiving UE through the PSFCH resource.

FIG. 22 shows a procedure for a receiving UE to determine PSFCHresource(s), based on an embodiment of the present disclosure. Theembodiment of FIG. 22 may be combined with various embodiments of thepresent disclosure.

Referring to FIG. 22 , in step S2210, the receiving UE maydetermine/select/allocate a PSFCH resource. For example, the receivingUE may select the PSFCH resource to be used for HARQ feedback, based onat least one of a slot corresponding to PSCCH transmission and/or PSSCHtransmission, sub-channel(s) corresponding to PSCCH transmission and/orPSSCH transmission, RB(s) corresponding to PSCCH transmission and/orPSSCH transmission, a cast type, a HARQ feedback method/option,information related to a PSSCH transmitting UE, information related toPSSCH transmission, or information related to a PSSCH receiving UE. Amethod in which the receiving UE determines the PSFCH resource may bethe same as the method in which the transmitting UE determines the PSFCHresource.

In step S2220, the receiving UE may receive the PSSCH and/or the PSCCHfrom the transmitting UE.

In step S2230, the receiving UE may transmit HARQ feedback for the PSSCHand/or the PSCCH to the transmitting UE through the PSFCH resource.

Based on various embodiments of the present disclosure, the UE/basestation may select/allocate the PSFCH resource. For example, the UE maydetermine a member ID based on a cast type and/or a HARQ feedbacktransmission method, and the UE may select/determine/allocate the PSFCHresource based on the member ID. Accordingly, an effect of efficientlysupporting the HARQ operation may occur.

FIG. 23 shows a method for a first device to determine a resource forreceiving HARQ feedback, based on an embodiment of the presentdisclosure. The embodiment of FIG. 23 may be combined with variousembodiments of the present disclosure. In the embodiment of FIG. 23 ,the order of each step may be changed.

Referring to FIG. 23 , in step S2310, the first device may determine aresource for a PSFCH. For example, the resource for the PSFCH may bedetermined based on at least one of a slot corresponding to PSCCHtransmission and/or PSSCH transmission, sub-channel(s) corresponding toPSCCH transmission and/or PSSCH transmission, RB(s) corresponding toPSCCH transmission and/or PSSCH transmission, a cast type, a HARQfeedback method/option, information related to a PSSCH transmitting UE,information related to PSSCH transmission, or information related to aPSSCH receiving UE. The first device may determine the resource for thePSFCH based on various embodiments proposed in the present disclosure.

In step S2320, the first device may transmit a PSSCH to a second device.In step S2330, the first device may receive HARQ feedback from thesecond device through the PSFCH related to the PSSCH.

The proposed method can be applied to the device(s) described below.First, the processor 102 of the first device 100 may determine aresource for a PSFCH. In addition, the processor 102 of the first device100 may control the transceiver 106 to transmit a PSSCH to the seconddevice 200. In addition, the processor 102 of the first device 100 maycontrol the transceiver 106 to receive HARQ feedback from the seconddevice 200 through the PSFCH related to the PSSCH.

FIG. 24 shows a method for a second device to determine a resource fortransmitting HARQ feedback, based on an embodiment of the presentdisclosure. The embodiment of FIG. 24 may be combined with variousembodiments of the present disclosure. In the embodiment of FIG. 24 ,the order of each step may be changed.

Referring to FIG. 24 , in step S2410, the second device may determine aresource for a PSFCH. For example, the resource for PSFCH may bedetermined based on at least one of a slot corresponding to PSCCHtransmission and/or PSSCH transmission, sub-channel(s) corresponding toPSCCH transmission and/or PSSCH transmission, RB(s) corresponding toPSCCH transmission and/or PSSCH transmission, a cast type, a HARQfeedback method/option, information related to a PSSCH transmitting UE,information related to PSSCH transmission, or information related to aPSSCH receiving UE. The second device may determine the resource for thePSFCH based on various embodiments proposed in the present disclosure.

In step S2420, the second device may receive a PSSCH from a firstdevice. In step S2430, the second device may transmit HARQ feedback tothe first device through the PSFCH related to the PSSCH.

The proposed method can be applied to the device(s) described below.First, the processor 202 of the second device 200 may determine aresource for a PSFCH. In addition, the processor 202 of the seconddevice 200 may control the transceiver 206 to receive a PSSCH from thefirst device 100. In addition, the processor 202 of the second device200 may control the transceiver 206 to transmit HARQ feedback to thefirst device 100 through the PSFCH related to the PSSCH.

FIG. 25 shows a method for a first device to perform wirelesscommunication, based on an embodiment of the present disclosure. Theembodiment of FIG. 25 may be combined with various embodiments of thepresent disclosure.

Referring to FIG. 25 , in step S2510, the first device may receive, froma second device, a physical sidelink shared channel (PSSCH). In stepS2520, the first device may determine a physical sidelink feedbackchannel (PSFCH) resource related to the PSSCH. In step S2530, the firstdevice may transmit, to the second device, a hybrid automatic repeatrequest (HARQ) feedback based on the PSFCH resource. For example, thePSFCH resource may be determined based on a sub-channel related to thePSSCH, a slot related to the PSSCH, a cast type of communication betweenthe first device and the second device, an ID of the first device, and asource ID of the second device.

For example, based on Table 5, the first device may determine one ormore PRBs for PSFCH transmission corresponding to the PSSCH received onthe i-th slot and the j-th subchannel.

TABLE 5 A UE is provided by rbSetPSFCH a set of M_(PRB, set) ^(PSFCH)PRBs in a resource pool for PSFCH transmission in a PRB of the resourcepool. For a number of N_(subch) sub-channels for the resource pool,provided by numSubchannel, and a number of N_(PSSCH) ^(PSFCH) PSSCHslots associated with a PSFCH slot, provided by periodPSFCHresource, theUE allocates the [(i + j · N_(PSSCH) ^(PSFCH)) · M_(subch, slot)^(PSFCH), (i + 1 + j · N_(PSSCH) ^(PSFCH)) · M_(subch, slot) ^(PSFCH) −1] PRBs from the M_(PRB, set) ^(PSFCH) PRBs to slot i and sub-channel j,where M_(subch, slot) ^(PSFCH) = M_(PRB, set) ^(PSFCH)/(N_(subch) ·N_(PSSCH) ^(PSFCH)), 0 ≤ i < N_(PSSCH) ^(PSFCH), 0 ≤ j < N_(subch), andthe allocation starts in an ascending order of i and continues in anascending order of j. The UE expects that M_(PRB, set) ^(PSFCH) is amultiple of N_(subch) · N_(PSSCH) ^(PSFCH).

In addition, based on Table 6, the first device may determine the numberof available PSFCH resources.

TABLE 6 A UE determines a number of PSFCH resources available formultiplexing HARQ-ACK information in a PSFCH transmission as R_(PRB, CS)^(PSFCH) = N_(type) ^(PSFCH) · M_(subch, slot) ^(PSFCH) · N_(CS)^(PSFCH) where N_(CS) ^(PSFCH) is a number of cyclic shift pairs for theresource pool and, based on an indication by higher layers, N_(type)^(PSFCH) = 1 and the M_(subch, slot) ^(PSFCH) PRBs are associated withthe starting sub-channel of the corresponding PSSCH N_(type) ^(PSFCH) =N_(subch) ^(PSSCH) and the N_(subch) ^(PSSCH) · M_(subch, slot) ^(PSFCH)PRBs are associated with one or more sub-channels from N_(subch)^(PSSCH) sub-channels of the corresponding PSSCH The PSFCH resources arefirst indexed according to an ascending order of the PRB index, from theN_(type) ^(PSFCH) · M_(subch, slot) ^(PSFCH) PRBs, and then according toan ascending order of the cyclic shift pair index from the N_(CS)^(PSFCH) cyclic shift pairs.

In addition, the first device may determine an index of the PSFCHresource based on Table 7. In addition, the first device may transmitHARQ feedback on the PSFCH resource corresponding to the index.Additionally, if the index is related to a specific cyclic shift, thefirst device may transmit HARQ feedback to which the specific cyclicshift is applied, based on the PSFCH resource corresponding to theindex.

TABLE 7 A UE determines an index of a PSFCH resource for a PSFCHtransmission in response to a PSSCH reception, as (P_(ID) + M_(ID))modR_(PRB, CS) ^(PSFCH) where P_(ID) is a physical layer source ID providedby SCI format 0_2 scheduling the PSSCH reception, M_(ID) is zero orM_(ID) is the identity of the UE receiving the PSSCH as indicated byhigher layers.

For example, the ID of the first device may be determined based on thecast type of communication between the first device and the seconddevice.

For example, the ID of the first device may be determined to be zero,based on the cast type being unicast.

For example, the ID of the first device may be determined to be anon-zero value, based on the cast type being groupcast based on a secondoption. For example, in the groupcast based on the second option, theHARQ feedback may be HARQ ACK based on successful decoding of data onthe PSSCH by the first device, and the HARQ feedback may be HARQ NACKbased on failure of decoding of data on the PSSCH by the first device.For example, the ID of the first device may be an ID allocated by ahigher layer.

For example, the ID of the first device may be determined to be zero,based on the cast type being groupcast based on a first option. Forexample, in the groupcast based on the first option, the HARQ feedbackmay be HARQ NACK based on failure of decoding of data on the PSSCH bythe first device, and the HARQ feedback may not be transmitted based onsuccessful decoding of data on the PSSCH by the first device.

For example, the PSFCH resource may be determined, among at least onePSFCH resource determined based on the sub-channel related to the PSSCHand the slot related to the PSSCH, based on the ID of the first devicerelated to the cast type and the source ID of the second device.

Additionally, for example, the first device may determine informationrelated to a cyclic shift applied to the HARQ feedback on the PSFCHresource. For example, the information related to the cyclic shiftapplied to the HARQ feedback on the PSFCH resource may be determinedbased on the ID of the first device. For example, the HARQ feedback maybe transmitted to the second device on the PSFCH resource based on theinformation related to the cyclic shift.

For example, the PSFCH resource may include at least one of a timedomain resource, a frequency domain resource, and a code domainresource.

Additionally, for example, the first device may receive, from the seconddevice, the source ID of the second device through a sidelink controlinformation (SCI).

The proposed method can be applied to the device(s) described below.First, the processor 102 of the first device 100 may control thetransceiver 106 to receive, from a second device, a physical sidelinkshared channel (PSSCH). In addition, the processor 102 of the firstdevice 100 may determine a physical sidelink feedback channel (PSFCH)resource related to the PSSCH. In addition, the processor 102 of thefirst device 100 may control the transceiver 106 to transmit, to thesecond device, a hybrid automatic repeat request (HARQ) feedback basedon the PSFCH resource. For example, the PSFCH resource may be determinedbased on a sub-channel related to the PSSCH, a slot related to thePSSCH, a cast type of communication between the first device and thesecond device, an ID of the first device, and a source ID of the seconddevice.

Based on an embodiment of the present disclosure, a first deviceconfigured to perform wireless communication may be provided. Forexample, the first device may comprise: one or more memories storinginstructions; one or more transceivers; and one or more processorsconnected to the one or more memories and the one or more transceivers.For example, the one or more processors may execute the instructions to:receive, from a second device, a physical sidelink shared channel(PSSCH); determine a physical sidelink feedback channel (PSFCH) resourcerelated to the PSSCH; and transmit, to the second device, a hybridautomatic repeat request (HARQ) feedback based on the PSFCH resource.For example, the PSFCH resource may be determined based on a sub-channelrelated to the PSSCH, a slot related to the PSSCH, a cast type ofcommunication between the first device and the second device, an ID ofthe first device, and a source ID of the second device.

Based on an embodiment of the present disclosure, an apparatusconfigured to control a first user equipment (UE) performing wirelesscommunication may be provided. For example, the apparatus may comprise:one or more processors; and one or more memories operably connected tothe one or more processors and storing instructions. For example, theone or more processors may execute the instructions to: receive, from asecond UE, a physical sidelink shared channel (PSSCH); determine aphysical sidelink feedback channel (PSFCH) resource related to thePSSCH; and transmit, to the second UE, a hybrid automatic repeat request(HARQ) feedback based on the PSFCH resource. For example, the PSFCHresource may be determined based on a sub-channel related to the PSSCH,a slot related to the PSSCH, a cast type of communication between thefirst UE and the second UE, an ID of the first UE, and a source ID ofthe second UE.

Based on an embodiment of the present disclosure, a non-transitorycomputer-readable storage medium storing instructions may be provided.For example, the instructions, when executed, may cause a first deviceto: receive, from a second device, a physical sidelink shared channel(PSSCH); determine a physical sidelink feedback channel (PSFCH) resourcerelated to the PSSCH; and transmit, to the second device, a hybridautomatic repeat request (HARQ) feedback based on the PSFCH resource.For example, the PSFCH resource may be determined based on a sub-channelrelated to the PSSCH, a slot related to the PSSCH, a cast type ofcommunication between the first device and the second device, an ID ofthe first device, and a source ID of the second device.

FIG. 26 shows a method for a second device to perform wirelesscommunication, based on an embodiment of the present disclosure. Theembodiment of FIG. 26 may be combined with various embodiments of thepresent disclosure.

Referring to FIG. 26 , in step S2610, the second device may transmit, toa first device, a physical sidelink shared channel (PSSCH). In stepS2620, the second device may determine a physical sidelink feedbackchannel (PSFCH) resource related to the PSSCH. In step S2630, the seconddevice may receive, from the first device, a hybrid automatic repeatrequest (HARQ) feedback based on the PSFCH resource. For example, thePSFCH resource may be determined based on a sub-channel related to thePSSCH, a slot related to the PSSCH, a cast type of communication betweenthe first device and the second device, an ID of the first device, and asource ID of the second device.

For example, based on Table 5, the second device may determine one ormore PRBs for PSFCH reception corresponding to the PSSCH transmitted onthe i-th slot and the j-th subchannel. In addition, based on Table 6,the second device may determine the number of available PSFCH resources.In addition, the second device may determine an index of the PSFCHresource based on Table 7. In addition, the second device may receiveHARQ feedback on the PSFCH resource corresponding to the index.Additionally, if the index is related to a specific cyclic shift, thesecond device may receive HARQ feedback to which the specific cyclicshift is applied, based on the PSFCH resource corresponding to theindex.

The proposed method can be applied to device(s) described below. First,the processor 202 of the second device 200 may control the transceiver206 to transmit, to a first device, a physical sidelink shared channel(PSSCH). In addition, the processor 202 of the second device 200 maydetermine a physical sidelink feedback channel (PSFCH) resource relatedto the PSSCH. In addition, the processor 202 of the second device 200may control the transceiver 206 to receive, from the first device, ahybrid automatic repeat request (HARQ) feedback based on the PSFCHresource. For example, the PSFCH resource may be determined based on asub-channel related to the PSSCH, a slot related to the PSSCH, a casttype of communication between the first device and the second device, anID of the first device, and a source ID of the second device.

Based on an embodiment of the present disclosure, a second deviceconfigured to perform wireless communication may be provided. Forexample, the second device may comprise: one or more memories storinginstructions; one or more transceivers; and one or more processorsconnected to the one or more memories and the one or more transceivers.For example, the one or more processors may execute the instructions to:transmit, to a first device, a physical sidelink shared channel (PSSCH);determine a physical sidelink feedback channel (PSFCH) resource relatedto the PSSCH; and receive, from the first device, a hybrid automaticrepeat request (HARQ) feedback based on the PSFCH resource. For example,the PSFCH resource may be determined based on a sub-channel related tothe PSSCH, a slot related to the PSSCH, a cast type of communicationbetween the first device and the second device, an ID of the firstdevice, and a source ID of the second device.

Based on an embodiment of the present disclosure, an apparatusconfigured to control a second user equipment (UE) performing wirelesscommunication may be provided. For example, the apparatus may comprise:one or more processors; and one or more memories operably connected tothe one or more processors and storing instructions. For example, theone or more processors may execute the instructions to: transmit, to afirst UE, a physical sidelink shared channel (PSSCH); determine aphysical sidelink feedback channel (PSFCH) resource related to thePSSCH; and receive, from the first UE, a hybrid automatic repeat request(HARQ) feedback based on the PSFCH resource. For example, the PSFCHresource may be determined based on a sub-channel related to the PSSCH,a slot related to the PSSCH, a cast type of communication between thefirst UE and the second UE, an ID of the first UE, and a source ID ofthe second UE.

Based on an embodiment of the present disclosure, a non-transitorycomputer-readable storage medium storing instructions may be provided.For example, the instructions, when executed, may cause a second deviceto: transmit, to a first device, a physical sidelink shared channel(PSSCH); determine a physical sidelink feedback channel (PSFCH) resourcerelated to the PSSCH; and receive, from the first device, a hybridautomatic repeat request (HARQ) feedback based on the PSFCH resource.For example, the PSFCH resource may be determined based on a sub-channelrelated to the PSSCH, a slot related to the PSSCH, a cast type ofcommunication between the first device and the second device, an ID ofthe first device, and a source ID of the second device.

Various embodiments of the present disclosure may be combined with eachother.

Hereinafter, device(s) to which various embodiments of the presentdisclosure can be applied will be described.

The various descriptions, functions, procedures, proposals, methods,and/or operational flowcharts of the present disclosure described inthis document may be applied to, without being limited to, a variety offields requiring wireless communication/connection (e.g., 5G) betweendevices.

Hereinafter, a description will be given in more detail with referenceto the drawings. In the following drawings/description, the samereference symbols may denote the same or corresponding hardware blocks,software blocks, or functional blocks unless described otherwise.

FIG. 27 shows a communication system 1, based on an embodiment of thepresent disclosure.

Referring to FIG. 27 , a communication system 1 to which variousembodiments of the present disclosure are applied includes wirelessdevices, Base Stations (BSs), and a network. Herein, the wirelessdevices represent devices performing communication using Radio AccessTechnology (RAT) (e.g., 5G New RAT (NR)) or Long-Term Evolution (LTE))and may be referred to as communication/radio/5G devices. The wirelessdevices may include, without being limited to, a robot 100 a, vehicles100 b-1 and 100 b-2, an eXtended Reality (XR) device 100 c, a hand-helddevice 100 d, a home appliance 100 e, an Internet of Things (IoT) device100 f, and an Artificial Intelligence (AI) device/server 400. Forexample, the vehicles may include a vehicle having a wirelesscommunication function, an autonomous vehicle, and a vehicle capable ofperforming communication between vehicles. Herein, the vehicles mayinclude an Unmanned Aerial Vehicle (UAV) (e.g., a drone). The XR devicemay include an Augmented Reality (AR)/Virtual Reality (VR)/Mixed Reality(MR) device and may be implemented in the form of a Head-Mounted Device(HMD), a Head-Up Display (HUD) mounted in a vehicle, a television, asmartphone, a computer, a wearable device, a home appliance device, adigital signage, a vehicle, a robot, etc. The hand-held device mayinclude a smartphone, a smartpad, a wearable device (e.g., a smartwatchor a smartglasses), and a computer (e.g., a notebook). The homeappliance may include a TV, a refrigerator, and a washing machine. TheIoT device may include a sensor and a smartmeter. For example, the BSsand the network may be implemented as wireless devices and a specificwireless device 200 a may operate as a BS/network node with respect toother wireless devices.

The wireless devices 100 a to 100 f may be connected to the network 300via the BSs 200. An AI technology may be applied to the wireless devices100 a to 100 f and the wireless devices 100 a to 100 f may be connectedto the AI server 400 via the network 300. The network 300 may beconfigured using a 3G network, a 4G (e.g., LTE) network, or a 5G (e.g.,NR) network. Although the wireless devices 100 a to 100 f maycommunicate with each other through the BSs 200/network 300, thewireless devices 100 a to 100 f may perform direct communication (e.g.,sidelink communication) with each other without passing through theBSs/network. For example, the vehicles 100 b-1 and 100 b-2 may performdirect communication (e.g. Vehicle-to-Vehicle(V2V)/Vehicle-to-everything (V2X) communication). The IoT device (e.g.,a sensor) may perform direct communication with other IoT devices (e.g.,sensors) or other wireless devices 100 a to 100 f.

Wireless communication/connections 150 a, 150 b, or 150 c may beestablished between the wireless devices 100 a to 100 f/BS 200, or BS200/BS 200. Herein, the wireless communication/connections may beestablished through various RATs (e.g., 5G NR) such as uplink/downlinkcommunication 150 a, sidelink communication 150 b (or, D2Dcommunication), or inter BS communication (e.g., relay, IntegratedAccess Backhaul (JAB)). The wireless devices and the BSs/the wirelessdevices may transmit/receive radio signals to/from each other throughthe wireless communication/connections 150 a and 150 b. For example, thewireless communication/connections 150 a and 150 b may transmit/receivesignals through various physical channels. To this end, at least a partof various configuration information configuring processes, varioussignal processing processes (e.g., channel encoding/decoding,modulation/demodulation, and resource mapping/demapping), and resourceallocating processes, for transmitting/receiving radio signals, may beperformed based on the various proposals of the present disclosure.

FIG. 28 shows wireless devices, based on an embodiment of the presentdisclosure.

Referring to FIG. 28 , a first wireless device 100 and a second wirelessdevice 200 may transmit radio signals through a variety of RATs (e.g.,LTE and NR). Herein, {the first wireless device 100 and the secondwireless device 200} may correspond to {the wireless device 100 x andthe BS 200} and/or {the wireless device 100 x and the wireless device100 x} of FIG. 27 .

The first wireless device 100 may include one or more processors 102 andone or more memories 104 and additionally further include one or moretransceivers 106 and/or one or more antennas 108. The processor(s) 102may control the memory(s) 104 and/or the transceiver(s) 106 and may beconfigured to implement the descriptions, functions, procedures,proposals, methods, and/or operational flowcharts disclosed in thisdocument. For example, the processor(s) 102 may process informationwithin the memory(s) 104 to generate first information/signals and thentransmit radio signals including the first information/signals throughthe transceiver(s) 106. The processor(s) 102 may receive radio signalsincluding second information/signals through the transceiver 106 andthen store information obtained by processing the secondinformation/signals in the memory(s) 104. The memory(s) 104 may beconnected to the processor(s) 102 and may store a variety of informationrelated to operations of the processor(s) 102. For example, thememory(s) 104 may store software code including commands for performinga part or the entirety of processes controlled by the processor(s) 102or for performing the descriptions, functions, procedures, proposals,methods, and/or operational flowcharts disclosed in this document.Herein, the processor(s) 102 and the memory(s) 104 may be a part of acommunication modem/circuit/chip designed to implement RAT (e.g., LTE orNR). The transceiver(s) 106 may be connected to the processor(s) 102 andtransmit and/or receive radio signals through one or more antennas 108.Each of the transceiver(s) 106 may include a transmitter and/or areceiver. The transceiver(s) 106 may be interchangeably used with RadioFrequency (RF) unit(s). In the present disclosure, the wireless devicemay represent a communication modem/circuit/chip.

The second wireless device 200 may include one or more processors 202and one or more memories 204 and additionally further include one ormore transceivers 206 and/or one or more antennas 208. The processor(s)202 may control the memory(s) 204 and/or the transceiver(s) 206 and maybe configured to implement the descriptions, functions, procedures,proposals, methods, and/or operational flowcharts disclosed in thisdocument. For example, the processor(s) 202 may process informationwithin the memory(s) 204 to generate third information/signals and thentransmit radio signals including the third information/signals throughthe transceiver(s)206. The processor(s) 202 may receive radio signalsincluding fourth information/signals through the transceiver(s) 106 andthen store information obtained by processing the fourthinformation/signals in the memory(s) 204. The memory(s) 204 may beconnected to the processor(s) 202 and may store a variety of informationrelated to operations of the processor(s) 202. For example, thememory(s) 204 may store software code including commands for performinga part or the entirety of processes controlled by the processor(s) 202or for performing the descriptions, functions, procedures, proposals,methods, and/or operational flowcharts disclosed in this document.Herein, the processor(s) 202 and the memory(s) 204 may be a part of acommunication modem/circuit/chip designed to implement RAT (e.g., LTE orNR). The transceiver(s) 206 may be connected to the processor(s) 202 andtransmit and/or receive radio signals through one or more antennas 208.Each of the transceiver(s) 206 may include a transmitter and/or areceiver. The transceiver(s) 206 may be interchangeably used with RFunit(s). In the present disclosure, the wireless device may represent acommunication modem/circuit/chip.

Hereinafter, hardware elements of the wireless devices 100 and 200 willbe described more specifically. One or more protocol layers may beimplemented by, without being limited to, one or more processors 102 and202. For example, the one or more processors 102 and 202 may implementone or more layers (e.g., functional layers such as PHY. MAC, RLC, PDCP,RRC, and SDAP). The one or more processors 102 and 202 may generate oneor more Protocol Data Units (PDUs) and/or one or more Service Data Unit(SDUs) according to the descriptions, functions, procedures, proposals,methods, and/or operational flowcharts disclosed in this document. Theone or more processors 102 and 202 may generate messages, controlinformation, data, or information according to the descriptions,functions, procedures, proposals, methods, and/or operational flowchartsdisclosed in this document. The one or more processors 102 and 202 maygenerate signals (e.g., baseband signals) including PDUs, SDUs,messages, control information, data, or information according to thedescriptions, functions, procedures, proposals, methods, and/oroperational flowcharts disclosed in this document and provide thegenerated signals to the one or more transceivers 106 and 206. The oneor more processors 102 and 202 may receive the signals (e.g., basebandsignals) from the one or more transceivers 106 and 206 and acquire thePDUs. SDUs, messages, control information, data, or informationaccording to the descriptions, functions, procedures, proposals,methods, and/or operational flowcharts disclosed in this document.

The one or more processors 102 and 202 may be referred to ascontrollers, microcontrollers, microprocessors, or microcomputers. Theone or more processors 102 and 202 may be implemented by hardware,firmware, software, or a combination thereof. As an example, one or moreApplication Specific Integrated Circuits (ASICs), one or more DigitalSignal Processors (DSPs), one or more Digital Signal Processing Devices(DSPDs), one or more Programmable Logic Devices (PLDs), or one or moreField Programmable Gate Arrays (FPGAs) may be included in the one ormore processors 102 and 202. The descriptions, functions, procedures,proposals, methods, and/or operational flowcharts disclosed in thisdocument may be implemented using firmware or software and the firmwareor software may be configured to include the modules, procedures, orfunctions. Firmware or software configured to perform the descriptions,functions, procedures, proposals, methods, and/or operational flowchartsdisclosed in this document may be included in the one or more processors102 and 202 or stored in the one or more memories 104 and 204 so as tobe driven by the one or more processors 102 and 202. The descriptions,functions, procedures, proposals, methods, and/or operational flowchartsdisclosed in this document may be implemented using firmware or softwarein the form of code, commands, and/or a set of commands.

The one or more memories 104 and 204 may be connected to the one or moreprocessors 102 and 202 and store various types of data, signals,messages, information, programs, code, instructions, and/or commands.The one or more memories 104 and 204 may be configured by Read-OnlyMemories (ROMs), Random Access Memories (RAMs), Electrically ErasableProgrammable Read-Only Memories (EPROMs), flash memories, hard drives,registers, cash memories, computer-readable storage media, and/orcombinations thereof. The one or more memories 104 and 204 may belocated at the interior and/or exterior of the one or more processors102 and 202. The one or more memories 104 and 204 may be connected tothe one or more processors 102 and 202 through various technologies suchas wired or wireless connection.

The one or more transceivers 106 and 206 may transmit user data, controlinformation, and/or radio signals/channels, mentioned in the methodsand/or operational flowcharts of this document, to one or more otherdevices. The one or more transceivers 106 and 206 may receive user data,control information, and/or radio signals/channels, mentioned in thedescriptions, functions, procedures, proposals, methods, and/oroperational flowcharts disclosed in this document, from one or moreother devices. For example, the one or more transceivers 106 and 206 maybe connected to the one or more processors 102 and 202 and transmit andreceive radio signals. For example, the one or more processors 102 and202 may perform control so that the one or more transceivers 106 and 206may transmit user data, control information, or radio signals to one ormore other devices. The one or more processors 102 and 202 may performcontrol so that the one or more transceivers 106 and 206 may receiveuser data, control information, or radio signals from one or more otherdevices. The one or more transceivers 106 and 206 may be connected tothe one or more antennas 108 and 208 and the one or more transceivers106 and 206 may be configured to transmit and receive user data, controlinformation, and/or radio signals/channels, mentioned in thedescriptions, functions, procedures, proposals, methods, and/oroperational flowcharts disclosed in this document, through the one ormore antennas 108 and 208. In this document, the one or more antennasmay be a plurality of physical antennas or a plurality of logicalantennas (e.g., antenna ports). The one or more transceivers 106 and 206may convert received radio signals/channels etc. from RF band signalsinto baseband signals in order to process received user data, controlinformation, radio signals/channels, etc. using the one or moreprocessors 102 and 202. The one or more transceivers 106 and 206 mayconvert the user data, control information, radio signals/channels, etc.processed using the one or more processors 102 and 202 from the baseband signals into the RF band signals. To this end, the one or moretransceivers 106 and 206 may include (analog) oscillators and/orfilters.

FIG. 29 shows a signal process circuit for a transmission signal, basedon an embodiment of the present disclosure.

Referring to FIG. 29 , a signal processing circuit 1000 may includescramblers 1010, modulators 1020, a layer mapper 1030, a precoder 1040,resource mappers 1050, and signal generators 1060. An operation/functionof FIG. 29 may be performed, without being limited to, the processors102 and 202 and/or the transceivers 106 and 206 of FIG. 28 . Hardwareelements of FIG. 29 may be implemented by the processors 102 and 202and/or the transceivers 106 and 206 of FIG. 28 . For example, blocks1010 to 1060 may be implemented by the processors 102 and 202 of FIG. 28. Alternatively, the blocks 1010 to 1050 may be implemented by theprocessors 102 and 202 of FIG. 28 and the block 1060 may be implementedby the transceivers 106 and 206 of FIG. 28 .

Codewords may be converted into radio signals via the signal processingcircuit 1000 of FIG. 29 . Herein, the codewords are encoded bitsequences of information blocks. The information blocks may includetransport blocks (e.g., a UL-SCH transport block, a DL-SCH transportblock). The radio signals may be transmitted through various physicalchannels (e.g., a PUSCH and a PDSCH).

Specifically, the codewords may be converted into scrambled bitsequences by the scramblers 1010. Scramble sequences used for scramblingmay be generated based on an initialization value, and theinitialization value may include ID information of a wireless device.The scrambled bit sequences may be modulated to modulation symbolsequences by the modulators 1020. A modulation scheme may includepi/2-Binary Phase Shift Keying (pi/2-BPSK), m-Phase Shift Keying(m-PSK), and m-Quadrature Amplitude Modulation (m-QAM). Complexmodulation symbol sequences may be mapped to one or more transportlayers by the layer mapper 1030. Modulation symbols of each transportlayer may be mapped (precoded) to corresponding antenna port(s) by theprecoder 1040. Outputs z of the precoder 1040 may be obtained bymultiplying outputs y of the layer mapper 1030 by an N*M precodingmatrix W. Herein, N is the number of antenna ports and M is the numberof transport layers. The precoder 1040 may perform precoding afterperforming transform precoding (e.g., DFT) for complex modulationsymbols. Alternatively, the precoder 1040 may perform precoding withoutperforming transform precoding.

The resource mappers 1050 may map modulation symbols of each antennaport to time-frequency resources. The time-frequency resources mayinclude a plurality of symbols (e.g., a CP-OFDMA symbols and DFT-s-OFDMAsymbols) in the time domain and a plurality of subcarriers in thefrequency domain. The signal generators 1060 may generate radio signalsfrom the mapped modulation symbols and the generated radio signals maybe transmitted to other devices through each antenna. For this purpose,the signal generators 1060 may include Inverse Fast Fourier Transform(IFFT) modules, Cyclic Prefix (CP) inserters, Digital-to-AnalogConverters (DACs), and frequency up-converters.

Signal processing procedures for a signal received in the wirelessdevice may be configured in a reverse manner of the signal processingprocedures 1010 to 1060 of FIG. 29 . For example, the wireless devices(e.g., 100 and 200 of FIG. 28 ) may receive radio signals from theexterior through the antenna ports/transceivers. The received radiosignals may be converted into baseband signals through signal restorers.To this end, the signal restorers may include frequency downlinkconverters, Analog-to-Digital Converters (ADCs), CP remover, and FastFourier Transform (FFT) modules. Next, the baseband signals may berestored to codewords through a resource demapping procedure, apostcoding procedure, a demodulation processor, and a descramblingprocedure. The codewords may be restored to original information blocksthrough decoding. Therefore, a signal processing circuit (notillustrated) for a reception signal may include signal restorers,resource demappers, a postcoder, demodulators, descramblers, anddecoders.

FIG. 30 shows another example of a wireless device, based on anembodiment of the present disclosure. The wireless device may beimplemented in various forms according to a use-case/service (refer toFIG. 27 ).

Referring to FIG. 30 , wireless devices 100 and 200 may correspond tothe wireless devices 100 and 200 of FIG. 28 and may be configured byvarious elements, components, units/portions, and/or modules. Forexample, each of the wireless devices 10 and 200 may include acommunication unit 110, a control unit 120, a memory unit 130, andadditional components 140. The communication unit may include acommunication circuit 112 and transceiver(s) 114. For example, thecommunication circuit 112 may include the one or more processors 102 and202 and/or the one or more memories 104 and 204 of FIG. 28 . Forexample, the transceiver(s) 114 may include the one or more transceivers106 and 206 and/or the one or more antennas 108 and 208 of FIG. 28 . Thecontrol unit 120 is electrically connected to the communication unit110, the memory 130, and the additional components 140 and controlsoverall operation of the wireless devices. For example, the control unit120 may control an electric/mechanical operation of the wireless devicebased on programs/code/commands/information stored in the memory unit130. The control unit 120 may transmit the information stored in thememory unit 130 to the exterior (e.g., other communication devices) viathe communication unit 110 through a wireless/wired interface or store,in the memory unit 130, information received through the wireless/wiredinterface from the exterior (e.g., other communication devices) via thecommunication unit 110.

The additional components 140 may be variously configured according totypes of wireless devices. For example, the additional components 140may include at least one of a power unit/battery, input/output (I/O)unit, a driving unit, and a computing unit. The wireless device may beimplemented in the form of, without being limited to, the robot (100 aof FIG. 27 ), the vehicles (100 b-1 and 100 b-2 of FIG. 27 ), the XRdevice (100 c of FIG. 27 ), the hand-held device (100 d of FIG. 27 ),the home appliance (100 e of FIG. 27 ), the IoT device (100 f of FIG. 27), a digital broadcast terminal, a hologram device, a public safetydevice, an MTC device, a medicine device, a fintech device (or a financedevice), a security device, a climate/environment device, the AIserver/device (400 of FIG. 27 ), the BSs (200 of FIG. 27 ), a networknode, etc. The wireless device may be used in a mobile or fixed placeaccording to a use-example/service.

In FIG. 30 , the entirety of the various elements, components,units/portions, and/or modules in the wireless devices 100 and 200 maybe connected to each other through a wired interface or at least a partthereof may be wirelessly connected through the communication unit 110.For example, in each of the wireless devices 100 and 200, the controlunit 120 and the communication unit 110 may be connected by wire and thecontrol unit 120 and first units (e.g., 130 and 140) may be wirelesslyconnected through the communication unit 110. Each element, component,unit/portion, and/or module within the wireless devices 100 and 200 mayfurther include one or more elements. For example, the control unit 120may be configured by a set of one or more processors. As an example, thecontrol unit 120 may be configured by a set of a communication controlprocessor, an application processor, an Electronic Control Unit (ECU), agraphical processing unit, and a memory control processor. As anotherexample, the memory 130 may be configured by a Random Access Memory(RAM), a Dynamic RAM (DRAM), a Read Only Memory (ROM)), a flash memory,a volatile memory, a non-volatile memory, and/or a combination thereof.

Hereinafter, an example of implementing FIG. 30 will be described indetail with reference to the drawings.

FIG. 31 shows a hand-held device, based on an embodiment of the presentdisclosure. The hand-held device may include a smartphone, a smartpad, awearable device (e.g., a smartwatch or a smartglasses), or a portablecomputer (e.g., a notebook). The hand-held device may be referred to asa mobile station (MS), a user terminal (UT), a Mobile Subscriber Station(MSS), a Subscriber Station (SS), an Advanced Mobile Station (AMS), or aWireless Terminal (WT).

Referring to FIG. 31 , a hand-held device 100 may include an antennaunit 108, a communication unit 110, a control unit 120, a memory unit130, a power supply unit 140 a, an interface unit 140 b, and an 110 unit140 c. The antenna unit 108 may be configured as a part of thecommunication unit 110. Blocks 110 to 130/140 a to 140 c correspond tothe blocks 110 to 130/140 of FIG. 30 , respectively.

The communication unit 110 may transmit and receive signals (e.g., dataand control signals) to and from other wireless devices or BSs. Thecontrol unit 120 may perform various operations by controllingconstituent elements of the hand-held device 100. The control unit 120may include an Application Processor (AP). The memory unit 130 may storedata/parameters/programs/code/commands needed to drive the hand-helddevice 100. The memory unit 130 may store input/output data/information.The power supply unit 140 a may supply power to the hand-held device 100and include a wired/wireless charging circuit, a battery, etc. Theinterface unit 140 b may support connection of the hand-held device 100to other external devices. The interface unit 140 b may include variousports (e.g., an audio I/O port and a video I/O port) for connection withexternal devices. The I/O unit 140 c may input or output videoinformation/signals, audio information/signals, data, and/or informationinput by a user. The I/O unit 140 c may include a camera, a microphone,a user input unit, a display unit 140 d, a speaker, and/or a hapticmodule.

As an example, in the case of data communication, the I/O unit 140 c mayacquire information/signals (e.g., touch, text, voice, images, or video)input by a user and the acquired information/signals may be stored inthe memory unit 130. The communication unit 110 may convert theinformation/signals stored in the memory into radio signals and transmitthe converted radio signals to other wireless devices directly or to aBS. The communication unit 110 may receive radio signals from otherwireless devices or the BS and then restore the received radio signalsinto original information/signals. The restored information/signals maybe stored in the memory unit 130 and may be output as various types(e.g., text, voice, images, video, or haptic) through the I/O unit 140c.

FIG. 32 shows a vehicle or an autonomous vehicle, based on an embodimentof the present disclosure. The vehicle or autonomous vehicle may beimplemented by a mobile robot, a car, a train, a manned/unmanned AerialVehicle (AV), a ship, etc.

Referring to FIG. 32 , a vehicle or autonomous vehicle 100 may includean antenna unit 108, a communication unit 110, a control unit 120, adriving unit 140 a, a power supply unit 140 b, a sensor unit 140 c, andan autonomous driving unit 140 d. The antenna unit 108 may be configuredas a part of the communication unit 110. The blocks 110/130/140 a to 140d correspond to the blocks 110/130/140 of FIG. 30 , respectively.

The communication unit 110 may transmit and receive signals (e.g., dataand control signals) to and from external devices such as othervehicles, BSs (e.g., gNBs and road side units), and servers. The controlunit 120 may perform various operations by controlling elements of thevehicle or the autonomous vehicle 100. The control unit 120 may includean Electronic Control Unit (ECU). The driving unit 140 a may cause thevehicle or the autonomous vehicle 100 to drive on a road. The drivingunit 140 a may include an engine, a motor, a powertrain, a wheel, abrake, a steering device, etc. The power supply unit 140 b may supplypower to the vehicle or the autonomous vehicle 100 and include awired/wireless charging circuit, a battery, etc. The sensor unit 140 cmay acquire a vehicle state, ambient environment information, userinformation, etc. The sensor unit 140 c may include an InertialMeasurement Unit (IMU) sensor, a collision sensor, a wheel sensor, aspeed sensor, a slope sensor, a weight sensor, a heading sensor, aposition module, a vehicle forward/backward sensor, a battery sensor, afuel sensor, a tire sensor, a steering sensor, a temperature sensor, ahumidity sensor, an ultrasonic sensor, an illumination sensor, a pedalposition sensor, etc. The autonomous driving unit 140 d may implementtechnology for maintaining a lane on which a vehicle is driving,technology for automatically adjusting speed, such as adaptive cruisecontrol, technology for autonomously driving along a determined path,technology for driving by automatically setting a path if a destinationis set, and the like.

For example, the communication unit 110 may receive map data, trafficinformation data, etc. from an external server. The autonomous drivingunit 140 d may generate an autonomous driving path and a driving planfrom the obtained data. The control unit 120 may control the drivingunit 140 a such that the vehicle or the autonomous vehicle 100 may movealong the autonomous driving path according to the driving plan (e.g.,speed/direction control). In the middle of autonomous driving, thecommunication unit 110 may aperiodically/periodically acquire recenttraffic information data from the external server and acquiresurrounding traffic information data from neighboring vehicles. In themiddle of autonomous driving, the sensor unit 140 c may obtain a vehiclestate and/or surrounding environment information. The autonomous drivingunit 140 d may update the autonomous driving path and the driving planbased on the newly obtained data/information. The communication unit 110may transfer information about a vehicle position, the autonomousdriving path, and/or the driving plan to the external server. Theexternal server may predict traffic information data using AItechnology, etc., based on the information collected from vehicles orautonomous vehicles and provide the predicted traffic information datato the vehicles or the autonomous vehicles.

Claims in the present description can be combined in a various way. Forinstance, technical features in method claims of the present descriptioncan be combined to be implemented or performed in an apparatus, andtechnical features in apparatus claims can be combined to be implementedor performed in a method. Further, technical features in method claim(s)and apparatus claim(s) can be combined to be implemented or performed inan apparatus. Further, technical features in method claim(s) andapparatus claim(s) can be combined to be implemented or performed in amethod.

What is claimed is:
 1. A method for performing, by a first device,wireless communication, the method comprising: obtaining a set ofphysical resource blocks (PRBs) for physical sidelink feedback channel(PSFCH) transmission; receiving, from a second device, a physicalsidelink shared channel (PSSCH); allocating at least one PRB to asub-channel and a slot related to the PSSCH; and determining an index ofa PSFCH resource for PSFCH transmission, among the at least one PRB, inresponse to the reception of the PSSCH, based on an identifier (ID) ofthe first device and a source ID of the second device, wherein, based ona cast type related to the PSSCH which is unicast or negativeacknowledgement-only based groupcast, the ID of the first device iszero, and wherein, based on the cast type related to the PSSCH which ispositive-negative acknowledgement based groupcast, the ID of the firstdevice is an ID for identifying the first device among devicesperforming groupcast communication within a group.
 2. The method ofclaim 1, wherein only negative acknowledgement transmission is allowedin the negative acknowledgement-only based groupcast.
 3. The method ofclaim 1, wherein, based on the cast type related to the PSSCH which isthe positive-negative acknowledgement based groupcast, the ID of thefirst device for determining the index of the PSFCH resource is an IDallocated by a higher layer.
 4. The method of claim 1, wherein positiveacknowledgement transmission or negative acknowledgement transmission isallowed in the positive-negative acknowledgement based groupcast.
 5. Themethod of claim 1, further comprising: transmitting, to the seconddevice, hybrid automatic repeat request (HARQ) feedback based on thePSFCH resource.
 6. The method of claim 5, wherein, in the negativeacknowledgement-only based groupcast, the HARQ feedback includesnegative acknowledgement based on failure of decoding of data on thePSSCH by the first device.
 7. The method of claim 5, wherein, in thenegative acknowledgement-only based groupcast, the transmission of theHARQ feedback is skipped based on successful decoding of data on thePSSCH by the first device.
 8. The method of claim 5, further comprising:determining information related to a cyclic shift applied to the HARQfeedback on the PSFCH resource.
 9. The method of claim 8, wherein theinformation related to the cyclic shift applied to the HARQ feedback onthe PSFCH resource is determined based on the ID of the first device.10. The method of claim 8, wherein the HARQ feedback is transmitted tothe second device on the PSFCH resource based on the information relatedto the cyclic shift.
 11. The method of claim 1, wherein the source ID ofthe second device is included in a sidelink control information (SCI)received through the PSSCH.
 12. A first device adapted to performwireless communication, the first device comprising: one or moretransceivers; one or more processors; and one or more memories operablyconnected to the one or more processors and storing instructions that,when executed by the one or more processors, perform operationscomprising: obtaining a set of physical resource blocks (PRBs) forphysical sidelink feedback channel (PSFCH) transmission; receiving, froma second device, a physical sidelink shared channel (PSSCH); allocatingat least one PRB to a sub-channel and a slot related to the PSSCH; anddetermining an index of a PSFCH resource for PSFCH transmission, amongthe at least one PRB, in response to the reception of the PSSCH, basedon an identifier (ID) of the first device and a source ID of the seconddevice, wherein, based on a cast type related to the PSSCH which isunicast or negative acknowledgement-only based groupcast, the ID of thefirst device is zero, and wherein, based on the cast type related to thePSSCH which is positive-negative acknowledgement based groupcast the IDof the first device is an ID for identifying the first device amongdevices performing groupcast communication within a group.
 13. The firstdevice of claim 12, wherein only negative acknowledgement transmissionis allowed in the negative acknowledgement-only based groupcast.
 14. Thefirst device of claim 12, wherein, based on the cast type related to thePSSCH which is the positive-negative acknowledgement based groupcast,the ID of the first device for determining the index of the PSFCHresource is an ID allocated by a higher layer.
 15. A processing deviceadapted to control a first device, the processing device comprising: oneor more processors; and one or more memories operably connected to theone or more processors and storing instructions that, when executed bythe one or more processors, perform operations comprising: obtaining aset of physical resource blocks (PRBs) for physical sidelink feedbackchannel (PSFCH) transmission; receiving, from a second device, aphysical sidelink shared channel (PSSCH); allocating at least one PRB toa sub-channel and a slot related to the PSSCH; and determining an indexof a PSFCH resource for PSFCH transmission, among the at least one PRB,in response to the reception of the PSSCH, based on an identifier (ID)of the first device and a source ID of the second device, wherein, basedon a cast type related to the PSSCH which is unicast or negativeacknowledgement-only based groupcast, the ID of the first device iszero, and wherein, based on the cast type related to the PSSCH which ispositive-negative acknowledgement based groupcast, the ID of the firstdevice is an ID for identifying the first device among devicesperforming groupcast communication within a group.
 16. The processingdevice of claim 15, wherein only negative acknowledgement transmissionis allowed in the negative acknowledgement-only based groupcast.
 17. Theprocessing device of claim 15, wherein, based on the cast type relatedto the PSSCH which is the positive-negative acknowledgement basedgroupcast, the ID of the first device for determining the index of thePSFCH resource is an ID allocated by a higher layer.